Mechanical Properties of SLM-Printed Aluminium Alloys

Aboulkhair et al. ()AlSi10MgLaser power 200 W, layer thickness 25 µm, scan speed 550 mm/s, hatch spacing 80 µm, and scan strategy chess board.
Heat treatment: Solution treated at 520 °C for 1 h, water quenched to room temperature and then
aged for 6 h at 160 °C.Fatigue

• At lower stress levels, machining the samples improved the fatigue performance, but did not have any influence at higher stress levels.

  Mechanical Properties of SLM-Printed Aluminium Alloys

  Aboulkhair et al. ()AlSi10MgLaser power 200 W, layer thickness 25 µm, scan speed 550 mm/s, hatch spacing 80 µm, and scan strategy chess board.
  Heat treatment: Solution treated at 520 °C for 1 h, water quenched to room temperature and then
  aged for 6 h at 160 °C.Fatigue

  • At lower stress levels, machining the samples improved the fatigue performance, but did not have any influence at higher stress levels.

  • Heat treating the samples significantly improved the fatigue life, and it was found that at 94 MPa stress loading, the heat-treated samples outperformed their cast counterparts in terms of fatigue life.

  • The samples that were heat-treated and machined showed the best fatigue performance.

  Renishaw AM250[27]Aboulkhair et al. ()AlSi10MgLaser power 200 W, scan speed 550 mm/s, hatch spacing 130 µm, layer thickness 25 µm, and checkerboard scan strategy.
  Heat treatment: T6Tensile strength, compressive yield strength, nano-hardness

  • The printed parts had tensile strength better than the diecast parts.

  • After heat treatment, the hardness and the tensile strength of the printed parts reduced by about 20% and 12%, respectively, whereas the ductility increased by a factor of 2.8.

  • The compressive yield strength of the heat-treated parts was 169 ± 6 MPa which was approximately half the strength of the as-built parts.

  Renishaw AM250[11]Aboulkhair et al. ()AlSi10MgLaser power 200 W, point distance 80 µm, exposure time 140 µs, hatch spacing 130 µm, layer thickness 25 µm and checkerboard scan strategy.Tensile and compressive strength, nano-hardness

  • Uniform nano-hardness of 1.82 ± 0.01 GPa was observed in the SLMed samples due to the homogeneous distribution of Si particles segregating at α-Al grain boundaries.

  • Microhardness along the plane parallel to the build plane was found to be higher (109.7 ± 0.9 HV) than the plane perpendicular to the build plane (99.07 ± 2 HV).

  Renishaw AM250[12]Alghamdi and Haghshenas ()AlSi10MgTwo 400 W lasers at CalRAM Inc. were used, with default SLM 280 parameter set.
  Heat Treatment: T6, solutionising at 520 °C for 1 h, followed by water quench, then artificial ageing at 170 °C for 4 h.Nano-hardness

  • The nano-hardness of the heat-treated samples (1.56 ± 0.11 GPa) was reduced by 42% compared to the strength of the as-built samples (2.71 ± 0.12 GPa).

  • Heat treatment of the samples resulted in the change in microstructure from cellular grains to fragmented/spheroidised eutectic silicon particles.

  • The effect of the indentation size was observed in both as-built and heat-treated samples. With the decrease in the depth of indent, the hardness increased.

  400 W laser at CalRAM Inc.
  SLM 280[28]Amani et al. ()AlSi10MgLaser power 250 W, scanning speed 571 mm/s, layer thickness 60 µm, and argon gas atmosphere.Compression behaviour

  • Deformation behaviour of two face-centred cubic lattice structures with thin and thick struts was studied using both in-situ and ex-situ X-ray computed tomography technique.

  • A finite element model was developed using Gurson-Tvergaard-Needleman (GTN) porous plasticity model.

  • Simulations showed a fairly good agreement with the model&#;s prediction of fracture location.

  SLM 250[29]Anwar & Pham ()AlSi10MgLaser power 350 W, layer thickness 100 µm, laser speed 900 mm/s, and hatch spacing of 0.12 mm.Tensile strength

  • The quality of the as-built samples depended upon the velocity of the gas flow in the built chamber, the direction of laser scan with respect to the gas flow direction, and position of the part with respect to the chamber outlet location.

  • Higher ultimate tensile strength (UTS) values for parts printed with laser scan direction against the gas flow, with higher gas velocity, and closer to the outlet was observed.

  • When the laser scanning was in the direction of gas flow, a reduced accumulation of spatter powder particles was observed near the outlet.

  SLM Solutions 280 HL[30]Asgari et al. ()AlSi10MgLaser power 370 W, scanning speed mm/s, hatch distance 190 µm, powder layer thickness 30 µm, build platform pre-heating temperature 200 °C.
  Build orientation: Vertical and Horizontal.Dynamic compression, Split Hopkinson pressure bar testing

  • Increasing the strain rate from 150 s&#;1 to s&#;1 resulted in higher yield, peak flow stress, and ductility.

  • The texture evolution could be attributed to vertical build orientation than horizontal build orientation due to uniform and dense microstructure, while the texture is not affected by the deformation at high strain rates.

  EOS M290 machine [31]Aversa et al. ()A357Laser power 195 W, scan speed mm/s, layer thickness 30 µm, hatching distance 0.1 mm and stripe scanning strategy.Tensile

  • Effect of build plate heating on the tensile properties was evaluated and build plate heating temperatures of 140 °C and 170 °C were reported to yield highest tensile strength of 408 ± 5 MPa and a yield strength of 284 ± 3 MPa.

  • The platform heating induces artificial ageing within the print-parts during processing.

  • Low platform heating temperatures result in under-ageing whereas high platform heating temperatures result in over-ageing of the printed samples.

  EOS M270 Dual Mode system[32]Awd et al. ()AlSi10MgProcess parameters not disclosed.
  Build orientation: 0°, 45° and 90° with respect to the build plate.Tensile

  • The pore density of 90° built samples were seven times higher than the 0° built samples.

  • The 0° built samples displayed 8% higher tensile strength than the samples built at 90° orientation.

  • Samples fabricated along the 45° orientation had a significantly reduced fracture strain.

  M2 Cusing system[33]Baitimerov et al. ()AlSi12Laser power 200 W, layer thickness 50 µm, stripe hatch scanning strategy, powder dried at 100 °C for 1 h and the oxygen inside the build chamber was maintained below 500 ppm.Density

  • Using the optimised process parameters, a relative density > 99% was achieved.

  • The AlSi12 powder with good flowability and apparent density leads to good processability in SLM, while highly fine and spherically shaped powder particles result in poor processability.

  • The particles with nearly spherical shaped morphology exhibited very poor flowability, leading to high porosity levels.

  Sinterstation® Pro DM125 SLM System[34]Bao et al. ()AlSi10MgLaser power ranging 360 W&#;400 W, layer thickness 0.05 mm, laser scanning speed mm/s&#; mm/s, scan spacing 0.13&#;0.16 mm.Fatigue

  • The cyclic plasticity occurs when the longitudinal strain exceeds 0.9.

  • The failure of the printed parts was attributed to the presence of large density of secondary micro-voids.

  • The elongation of original defects along the loading direction is 10 times faster than that along the lateral side.

  BLT S310[35]Bassoli et al. ()A357Laser power 950 W, scan speed mm/s, spot size 400 µm, hatch distance 0.2 mm, layer thickness 50 µm, nitrogen gas chamber atmosphere, preheating temperature 200 °C and skin core scan strategy.Tensile, Fatigue

  • A 0.2% proof stress of 192 ± 17 MPa was found for as-built A357 samples built in the vertical orientation.

  • A fatigue strength of 60 ± 5.3 MPa was obtained.

  X Line R (Concept Laser)[36]Beretta et al. ()AlSi10MgLaser power 350 W, hatch distance 0.13 mm, scan speed mm/s, layer thickness 50 µm, preheating of build platform up to 150 °C.
  Build orientation: Horizontal (0°), Inclined (45°), and Vertical (90°).Fatigue strength

  • Moderate correlation between the surface features at the origin of the fracture and surface roughness of the printed parts was found.

  • Horizontal-built specimens had highest fatigue strength compared to inclined- and vertical-built specimens.

  • EIFS and fatigue life prediction models were developed and verified using experimental data. The estimated cycles to failure was found within factor of 0.5&#;2 of the experimental values.

  SLM 280HL v1.0 [37]Biffi et al. ()AlSi10MgPulsed wave laser: laser power 300 W, build platform temperature 170 °C, exposure time 120 µs, point distance 130 µm, spot size 130 µm, hatch distance 140 µm, layer thickness 25 µm and build chamber environment argon.
  Continuous wave laser: laser power 350 W, build platform temperature 150 °C, laser travel speed mm/s, spot size 80 µm, hatch distance 170 µm, layer thickness 50 µm and build environment argon.Compression

  • The continuous wave (CW) and pulsed wave (PW) showed similar Si network, however they varied in liquid melt pool. The continuous wave yielded better strength in compression, which resulted in reduced influence of the sample build orientation on compression behaviour.

  • The samples built with CW laser emission was found to have better compressive strength than those processed with PW.

  • The anisotropy is better exhibited in PW than CW.

  Renishaw AM 250 system
  SLM Solutions SLM 500 system[38]Boschetto et al. ()AlSi10MgLaser power 370 W, scan speed mm/s, hatch spacing 190 µm, layer thickness 30 µm, laser beam diameter 100 µm, hatch rotation 67°.Roughness

  • Surface roughness prediction model that incorporates the staircase effect and defects arising due to satellites particles in the feedstock powder and the balling effect was developed.

  • A case study on the surface roughness of a Pelton bucket was carried out, comparing the experimental values of surface roughness of curved complex surfaces to that of the model predicted data.

  EOSINT® M290 [39]Brandl et al. ()AlSi10MgLaser power 250 W, beam diameter 0.2 mm, layer thickness 50 µm, scanning speed 500 mm/s, scan spacing 0.15 mm and argon gas shielding, with and without build plate heating, build plate heating temperature 300 °C.
  Build orientation: 0°, 45°, and 90°.Fatigue (using tensile samples), fracture analysis

  • Post heat treatment was found to have the most considerable effect, whereas the build orientation was found to have the least considerable effect on fatigue resistance.

  • Heating the build plate to 300 °C tended to neutralize the anistotropy effects due to build orientation of the samples as well as enhanced the fatigue resistance.

  • The fatigue limit and the static tensile strength significantly correlate with each other.

  Trumpf TrumaForm LF130 powder-bed machine [40]Buchbinder et al. ()AlSi10MgLaser power 195 W, layer thickness 30 µm, scanning speed 800 mm/s, hatch distance 150 µm, hatch rotation 67°, preheating temperatures 100°, 150°, 200°, and 250°.Distortion

  • Distortions in part geometry reduced from 10.6 mm to nearly zero after preheating at 250 &#;.

  • Reduction in hardness along with better resistance to crack growth was observed when the build plate was preheated.

  • With preheating, lower temperature gradient results in lower thermal stresses in the printed parts.

  EOSINT M 270[41]Casati et al. ()AlSi10MgLaser power 340 W, hatch distance 0.2 mm, scan rate mm/s, layer thickness 30 µm, platform temperature 160 °C.Tensile

  • Ageing of parts printed on cold-platform resulted in higher hardness and tensile strength compared to hot-platform printed and aged parts.

  • The standard T6 temper heat treatment resulted in higher ductility but lower mechanical strength.

  EOS M290 SLM system[42]Ch et al. ()AlSi10MgLaser power 370 W, scan speed mm/s, hatch spacing 0.19 mm, layer thickness 30 µm, preheating up to 300 °C.
  Build orientation: Horizontal and Vertical.Tensile, surface roughness, porosity, fracture morphology

  • The samples built under both argon and nitrogen exhibited similarity in defect structure, microstructure and nearly isotropic behaviour in mechanical properties.

  • In the vertical orientation under nitrogen atmosphere, samples exhibited tensile strength of 385 ± 5 MPa, whereas, at horizontal orientation under argon atmosphere, samples exhibited the lowest strength of 338 ± 2 MPa.

  • The meso-structure and microstructure of the material revealed the characteristic nature of SLMed AlSi10Mg alloy which contains melt pool tracks, columnar grains and cellular structure.

  EOS M280 machine[43]Chen et al. ()AlSi10MgLaser power 350 W, scan speed mm/s, layer thickness 50 µm, hatch spacing 240 µm. Tensile

  • Orowan looping leads to high strength and high strain hardening capability.

  • The hierarchical structure yields high yield strength of 300 MPa and UTS of 455 MPa.

  SLM 250HL, SLM Solutions[44]Chou et al. ()AlSi12Laser power 0.5&#;4.5 kW, travel speed 90&#;180 mm/min, spot size 150 µm, hatch distance 0.1 mm, layer thickness 0.1 mm.Hardness, density

  • Using pulsed laser for printing was demonstrated wherein Si refinement to size below 200 nm was achieved.

  • The print part density was 95% and hardness was 135 HV when using pulsed laser for fabrication.

  In house built Pulsed-SLM facility[45]Chou et al. ()A356 (AlSi7Mg0.3) Laser power (peak) 5 kW, square pulse, hatch distance 0.1 mm, layer thickness 100 µm, bidirectional zigzag scanning pattern, argon atmosphere.Density

  • Dense parts (98 ± 0.4%) were fabricated using customized pulsed laser SLM system.

  • Hunt&#;s criterion predicted primarily a columnar grain structure throughout the pulsed laser printed parts which was confirmed through electron backscatter diffraction (EBSD) observations.

  In house built Pulsed-SLM facility[21]Dai and Gu ()AlSi10Mg compositeLaser power 180 W, scan speed 100, 200, 300, and 400 mm/s, laser energy per unit length (LEPUL) 450, 600, 900, and J/m.Numerical simulation, thermodynamics of the molten pool

  • The oxidation played a significant role in the melt pool dynamics with thermo-capillary convection where convection took place from inward to outward flow pattern.

  • The thermocapillary flow yields a driving force for the migration and rearrangement of reinforcing particles in the melt pool.

  In house SLM [46]Dai et al. ()AlSi10Mg compositeLaser power 200 W, layer thickness 30 µm, scanning speed 100&#;300 mm/s, hatch spacing 60&#;100 µm.Wear

  • The wear resistance was significantly influenced by the densification rate, distribution state and the powder particle size.

  • Lowest wear rate of 3.4 × 10&#;4 mm3 N&#;1 m&#;1 was found when using an optimised laser volume energy density of 420 J/mm3.

  In house SLM [47]de Menezes et al. ()A357Laser power 200 W, layer thickness 25 µm, hatch distance 115 µm.
  Isothermal aging at 160 °C for 4 h.Tensile

  • The yield strength of the horizontal-built samples was considerably greater than that of the vertical-built samples.

  • The yield strength of the samples in artificially aged condition was greater than the as-built condition.

  • A crack orthogonal to the building orientation results in a significant decrease in fracture toughness of the printed samples.

  Renishaw AM250 SLM system[48]Delahaye et al. ()AlSi10MgLaser power 175 W, scan speed 195 mm/s, layer thickness 60 µm, preheating temperature 200 °C.Nanohardness, fracture morphology, tensile

  • The fracture likely occurs in the heat-affected zone (HAZ) region due to the presence of coarse non-coherent Si precipitates.

  • The intercellular network of eutectic structure is partially broken in the HAZ regions, thereby facilitating dislocation slip and plastic strain localisation.

  • The cells size of the HAZ was found to match with the size of the dimples on the fracture surfaces.

  MTT SLM 250[49]Deleroisse et al. ()AlSi10MgLaser power 250 W, scan speed 571 mm/s, layer thickness 60 µm, and argon atmosphere.
  Heat treatment: T6 heat treatment, annealing at 525 °C for 5 h, water quench and then artificial ageing at 165 °C for 7 h.Porosity, strut properties

  • Large levels of porosity and heterogenous microstructure was observed in inclined strut.

  • Amount of hydrogen detected in the samples was larger than the hydrogen solubility in the liquid melt pool.

  • Heat treatment suppresses microstructural heterogeneities.

  -[50]Denti ()A357Laser power 950 W, scanning speed mm/s, hatch distance 0.2 mm, laser spot 400 µm, nitrogen chamber atmosphere, preheated at 200 °C and skin-core scan strategy.Shear, Tensile

  • Yield strength (195 ± 17 MPa) and modulus (77.8 ± 6.8 GPa) were found to be maximum at 45° inclined samples.

  • The ultimate tensile strength and shear strength of vertical-built samples were found to be the highest, 305 ± 15 MPa and 192 ± 9 MPa, respectively.

  Concept Laser X Line R[51]Ding and Wang ()AlSi10MgLaser power 400 W, laser beam radius 67.5 µm, hatch space 130 µm, scan speed 300 mm/s.Modelling and simulation, density, hardness

  • There is negligible effect of exposure time on heat transfer, fluid flow, and melt pool dimension.

  • The simulated temperature and melt pool dimensions increase with an increase in point distance.

  -[52]Dong et al. ()AlSi10MgLaser power 370 W, laser spot size 100 µm, hatch spacing 190 µm, scanning speed mm/s, layer thickness 30 µm, argon chamber atmosphere.Tensile, porosity, fractography

  • The size effect has a significant influence on the geometric imperfection for SLM-processed AlSi10Mg strut.

  • The porosity level of the sample decreased from 1.87% to 0.1% with the variation of build size from 1 mm to 5 mm.

  • The overall strength and modulus decreased by approximately 30% with decrease in the build size.

  Concept X-line R machine [53]Everitt et al. ()AlSi10MgLaser power 100 W, scan speed 250 mm/s, hatch space 50 µm, argon atmosphere.Nanohardness

  • Chemical composition mapping and nano-indentation showed higher hardness in the SLM material compared to its cast counterpart.

  • The printed samples exhibited a nanohardness of 9 ± 1 GPa, compared to 0.97 ± 1 GPa for the cast samples.

  Realizer SLM-50[54]Fefelov et al. ()AlSi12-Fracture surface morphology, tensile

  • The samples demonstrated yield and tensile strengths of about 102 MPa and 425 MPa, respectively, along with fracture strain of 12%.

  EOSINT M 280 device[55]Fiegl et al. ()AlSi10MgLaser power W, layer thickness of 50 µm, volume energy 40 J/mm3, island scanning strategy and nitrogen atmosphere.Tensile

  • The impact of preheating on tensile strength in x/y plane seems to be more pronounced than the impact of beam deflection.

  • UTS was found to be higher without preheating, 377 ± 16 MPa, compared to samples printed with preheating strategy, 355 ± 15 MPa.

  X LINE R (modified)[56]Fiocchi et al. ()AlSi10MgLaser power 300 W, spot size 130 µm, layer thickness 25 µm, hatch distance 140 µm, and argon atmosphere.Differential scanning calorimetry, hardness

  • Two exothermic phenomena involving Mg2Si precipitation and Si diffusion were found.

  • Isothermal transformation temperatures were identified to be 263 °C and 294 °C.

  Renishaw AM250[57]Fousova et al. ()AlSi10MgLaser power 350 W, layer thickness 50 µm, scanning speed 500 mm/s, hatch spacing 170 µm, argon atmosphere and chessboard scanning strategy.Tensile

  • Printed samples subjected to elevated temperatures underwent microstructural and mechanical property changes.

  • At the tested temperature of 160 °C, a slight increase in tensile yield strength (by 5%) but also a strong reduction in elongation (by 60%) were observed.

  SLM Solution 280HL machine[58]Gokuldoss Prashanth et al. ()AlSi12Laser power 320 W, scan speed mm/s, layer thickness 50 µm, hatch spacing 110 µm and argon atmosphere.Tensile

  • The as-built samples exhibited a yield strength of 240 ± 1 MPa and UTS of 385 ± 4 MPa.

  • After annealing at 300 °C, the yield strength and UTS reduced to 138 ± 3 MPa and 205 ± 5 MPa, respectively.

  • The softening behaviour of the Al matrix was inversely proportional to strain hardening behaviour.

  SLM 250 HL[18]Girelli et al. ()AlSi10MgLaser power 400 W, beam diameter 100 µm, argon atmosphere.
  Build orientation: Horizontal and Vertical
  Heat treatment: Solutionising at 540 °C for 1&#;9 h, followed by ageing at 160 °C for 4 h or 180 °C for 2 h.Impact properties, fracture morphology

  • The fracture in the horizontal samples propagated along the hatch overlap regions whereas in the vertical samples the crack propagation was primarily along the inter-layer regions.

  • The building orientation has a significant influence on the properties of the printed samples even after post heat treatment is applied.

  • After hot isostatic pressing the samples, the porosity reduced considerably, and the fracture toughness of the specimens improved.

  EOS M290 system[59]Gong et al. ()AlSi10Mg-Tensile

  • The mechanical properties of AlSi10Mg parts produced by SLM are much higher than the alloy formed by conventional casting.

  -[60]Hadadzadeh et al. ()AlSi10MgLaser power 370 W, beam spot size 100 µm, scanning speed mm/s, hatch spacing 190 µm, layer thickness 30 µm, argon atmosphere.
  Build orientation: Horizontal and Vertical.Dynamic compression

  • Columnar cellular structure was observed in the horizontal-built samples, whereas equiaxed structure was observed in the vertical-built samples.

  • The dislocation density in the as-built horizontal and vertical samples was 1.14 × m&#;2 and 3.05 × m&#;2, respectively.

  • These dislocation networks converted to low angle grain boundaries through dynamic recovery process to reduce the energy, thereby resulting in softening of the samples.

  EOS M290 machine[61]Hadadzadeh et al. ()AlSi10MgLaser power 370 W, scanning speed mm/s, hatch spacing 190 µm, layer thickness 30 µm, stripe scanning strategy, argon atmosphere.Dynamic compression

  • The samples exhibited strain hardening at strain rates lower than s&#;1, and at higher strain rates they displayed double peak flow stress deformation regime.

  • Strengthening mechanisms included Hall-Petch contributed by cell walls, Orowon contributed by Si precipitates, and dislocation hardening.

  • Both cell walls and Si precipitates contribute to impeding the dislocation motion and development of dislocation networks.

  EOS M290[62]Han and Jiao ()AlSi10MgLaser power 200 W, hatch spacing 130 µm, layer thickness 25 µm, scanning speed 500 mm/s, chessboard bidirectional scanning strategy.
  Heat treatment: Solution-treated at 550 °C for 2 h, followed by furnace cooling.
  Laser surface remelting treatment: Laser power 20 W, beam diameter 32 µm, scanning speed 300 mm/s, layer thickness 0.01 mm.Tensile, Hardness, Roughness

  • The surface roughness of the laser surface remelted samples was significantly reduced (0.93 µm) compared to the as-built samples (19.3 µm).

  • The yield strength reduced from 200 MPa in the as-built samples to 100 MPa in the heat-treated samples.

  • The laser surface remelting process improved the microhardness by 19.5% through refining the microstructure.

  Renishaw AM250[63]Hatamleh et al. ()A357Heat treated at 170 °C for 3 h.
  Laser shock peening applied.Finite element analysis, residual stress analysis, tensile testing

  • Laser shock peening induced tensile residual stresses within certain regions of the samples.

  • Tensile tests were conducted, and the results were evaluated with finite element analysis by using Johnson-Cook parameters.

  -[64]Hitzler et al. ()AlSi10Mg Tensile

  • Post heat-treatment resulted in homogeneous microstructure, thereby exhibiting remarkable improvement in ductility.

  SLM 280HL machine[65]Hitzler et al. ()AlSi10MgLaser power 350 W, hatch spacing 0.42 mm, scan speeds 600&#;930 mm/s, base plate heating 200 °C.
  Build orientation: horizontal, inclined (45°), and vertical.Fracture toughness

  • The fracture toughness was found to be 40.63 KMPa.m0.5.

  • The vertical-built samples were found to have poor fracture toughness.

  SLM 280HL machine[66]Hitzler et al. ()AlSi10MgLaser power 350 W, hatch spacing 0.42 mm, scan speeds 600&#;930 mm/s, base plate heating 200 °C, nitrogen atmosphere.Tensile, surface hardness

  • The elastic modulus, tensile strength, and elongation were found to be sensitive to the part print orientation.

  • For the non-heat-treated condition, the Young&#;s modulus varied from 62.5 to 72.9 GPa, the Poisson&#;s ratio ranged from 0.29 to 0.36, UTS from 314 MPa to 399 MPa, and elongation from 3.2% to 6.5%.

  • The heat-treated samples exhibited dissimilar responses to an additional aging procedure and were dependent on the build height.

  SLM 280HL machine[67]Hitzler et al. ()AlSi10MgLaser power 400 W, layer thickness 50 µm, nitrogen atmosphere.Tensile, compression

  • Young&#;s modulus of the printed samples exceeded the nominal value of &#;70 GPa.

  • Vertical-built samples showed the least elastic modulus.

  • A maximum compressive strength value of 530 MPa was attained.

  SLM 280HL machine[68]Hu et al. ()AlSi10MgLaser energy input 700&#; J/m, layer thickness 50 µm, argon atmosphere.CFD model, thermal gradient

  • The results show that the temperature and molten pool depth gradually increases with new layers and energy input.

  • The cooling rate increases progressively while the solidification morphology parameter decreases with the increase of energy input.

  • The increase in energy input lead to non-linear increase in melt pool depth and remelting depth.

  -[69]Iturrioz et al. ()AlSi10MgLaser power 400 W, protective atmosphere.
  Heat treatment: Stress-relieving (heating rate of 10 °C/min until 300 °C for 2 h), Solution-treated at 450 °C and 550 °C for 2 h, followed by water quenching, and T6 heat treatment.Tensile, hardness, density

  • The as-built samples achieved a relative density of 99.9%. After heat treatments, Si forms polygonal precipitates whose size increases as the temperature increases. This results in a decrease in tensile strength and hardness with heating up to 450 °C.

  • T6 heat treatment (550 °C for 2 h followed by ageing at 180 °C for 12 h) was found to be best performing, which yielded the tensile strength of 307 ± 8 MPa, hardness 101 ± 4 HV and ductility 9 ± 3%.

  SLM 280HL machine[70]Jawade et al. ()AlSi10MgLaser power 250 W, beam diameter 0.2 mm, layer thickness 50 µm, scanning speed 500 mm/s. Tensile

  • The horizontal build orientation yielded better tensile strength when compared to samples built in the vertical orientation. Furthermore, microstructure revealed anisotropy and its dependency on build orientation.

  • The UTS was found to be maximum on horizontal orientation (401.89 MPa), yield strength (301.26 MPa) and elongation of 4.3%, which is superior than the counterpart at vertical orientation.

  Renishaw AM 250[71]Jiang et al. ()AlSi10Mg compositeLaser power 370 W, scan speed ranging from 900&#; mm/s, scan spacing 105 µm, layer thickness 30 µm, zigzag scan strategy. Tensile, hardness, density

  • The hardness and tensile strength improved by approx. 10% and 20%, respectively, with the addition of 1 wt% CNTs.

  Concept Laser M2 Cusing SLM system [72]Jing et al. ()AlSi10MgHatch spacing 190 µm, layer thickness 30 µm, volume energy density 26&#;54 Jmm&#;3, laser power 310&#;390 W, scanning speed &#; mm/s, chamber pressure 0.45 mbar.
  Build orientation: Horizontal and Vertical.Porosity, microhardness, tensile testing and fracture morphology

  • Microstructure of the samples printed using optimised process parameters consisted of extremely fine Al-Si eutectic dispersed within primary α-Al dendrites.

  • Hardness in the transverse direction was higher than that along the longitudinal direction.

  • The engineering stress-strain curve at different orientations also shows anisotropy in the strength and ductility, which is possibly due to the orientation between the tensile stress and crystal growth direction.

  EOS 83 M290 SLM[73]Kang et al. ()AlSi12Laser power 400 W, scanning speed mm/s, layer thickness 50 µm and hatch distance 45 µm.Tensile

  • Ultrafine microstructure consisting of cellular α-Al and nano-sized Si particles was found due to the high cooling rate of the SLM process

  • As the laser scanning speed increases, both tensile strength and ductility of SLM processed samples decrease.

  • Higher energy density was required to fabricate dense samples from in-situ SLM fabrication using elemental Al and Si powders, compared to pre-alloyed Al-12Si powders.

  Realizer SLM 250 machine[74]Kempen et al. ()AlSi10Mg200 W fiber laser, laser beam diameter 150 µm, scan speed mm/s, scan spacing 105 µm.
  Build orientation: Horizontal and Vertical.Tensile

  • Mechanical properties of printed parts comparable or even exceeding those of conventionally cast AlSi10Mg.

  • Maximum UTS observed for vertical samples 396 ± 8 MPa, but the elongation was better for the horizontal orientation 5.55 ± 0.4%.

  Modified Concept Laser M1 SLM Machine[4]Kempen et al. ()AlSi10MgLaser power 300 W, laser spot size 80 µm, scan speed mm/s.
  Build orientation: XY and Z.Surface roughness, Metrology

  • Samples printed in the Z-orientation has to be compensated for the width of the melt pool.

  • Samples printed in the XY-orientation showed dross formation.

  In-house built SLM machine[75]Kempen et al. ()AlSi10Mg200 W fiber laser, laser beam diameter 150 µm, scan speed mm/s, scan spacing 105 µm and layer thickness 30 µm.
  Build orientation: Horizontal and Vertical.Tensile, Hardness

  • Mechanical properties of printed parts comparable or even exceeding those of high pressure die cast AlSi10Mg.

  • Hardness found to be 152 ± 5 HV after ageing at 175 °C for 6 h.

  Modified Concept Laser M1 SLM Machine[76]Kempen et al. ()AlSi10Mg170 to 200 W fiber laser, laser beam diameter 150 µm, scan speed 200&#; mm/s, scan spacing 105 µm and layer thickness 30 µm.
  Build orientation: Horizontal and Vertical.Density, Roughness

  • Narrow process window to obtain optimal density and surface quality for printed parts.

  • Higher scan speed of mm/s was used for high density/productivity demands, whereas lower scan speeds of &#; mm/s were used for parts with a high demand in top surface quality.

  Modified Concept Laser M1 SLM Machine[77]Kim et al. ()AlSi10MgLaser power 200 W, scanning speed mm/s, bidirectional scanning vector.Tensile

  • Significant stress partitioning exists between the Si (680 MPa) and Al (260 MPa) constituents.

  • The fracture analysis reveals large voids and cracks in the microstructure, particularly in the soft Al matrix under loading.

  Concept Laser M2 machine[78]Kimura and Nakamoto ()A356Laser power 200&#;370 W, scan speed 400&#; mm/s, scan spacing 0.08&#;0.18 mm, layer thickness of 30 µm.Tensile, Density

  • Relative density of 99.8% could be obtained by optimizing the laser irradiation conditions.

  • Tensile strength of 400 MPa, yield strength of 200 MPa, and elongation of 12&#;17% was obtained for optimally printed samples.

  • After annealing the UTS reduced to 250 MPa and yield strength to 125 MPa, however, elongation increased to 30%.

  EOSINT M280 SLM [20]Krishnan et al. ()AlSi10Mg200 W Yb fiber laser, layer thickness 20&#;40 µm, beam diameter 0.1 mm, laser power 180&#;195 W, scanning speed 700&#;900 mm/s, hatch distance 0.1&#;0.25 mm, nitrogen atmosphere.Hardness, Density

  • Hatch distance is the most influential process parameter affecting the print part density.

  • There is a close correlation between the geometry of scan tracks and macroscopic properties of the printed parts.

  • The optimal energy density was found to be 1.2&#;1.8 J/mm2.

  -[79]Li et al. ()AlSi10MgLaser power 350 W, beam diameter 80 µm, scan speed mm/s, layer thickness 50 µm, scan spacing 170 µm, argon chamber atmosphere, substrate plate pre-heated to 100 °C.
  Heat treatment: T6 treatment, solution treated at 450 °C, 500 °C, and 550 °C for 2 h, water quenched, and aged at 180 °C for 12 h.Tensile, hardness

  • The solubility of Si in the Al matrix of the as-built samples was found to be about 8.89 at%, which significantly decreased after solution heat treatment, and further decreased with ageing treatment.

  • The tensile strength decreased from 434.25 ± 10.7 MPa for the as-built specimens to 168.11 ± 2.4 MPa for the specimens that were solution heat-treated only. However, the fracture strain increased from 5.3 ± 0.22% to 23.7 ± 0.84%.

  SLM250 HL[80]Li et al. ()AlSi10MgBuild orientation: Horizontal (Y-direction) and Vertical (Z-direction), tensile testing carried out at &#;71 °C. Tensile

  • The tensile strength and elongation of the horizontally-built samples are 340 MPa and 11.2%, respectively, compared to 350 MPa and 13.4%, respectively, for the vertically-built samples.

  • The microstructure revealed fish-scale morphology along the Y-build direction and oval shaped structure in the Z-build direction.

  -[81]Li et al. ()AlSi12Laser power 200 W, scanning speed 500 mm/s, layer thickness 50 µm, scan spacing 150 µm, substrate heated to 200 °C, argon atmosphere.
  Heat treatment: Solution treated at 500 °C for 4 h and water quenched.Tensile, residual stresses, FEM

  • Spherical Si particles with size less than 100 nm formed at the Al grain boundaries. However, the coarse and fine Si precipitates were found to be homogeneously distributed in the Al matrix.

  • The ultrafine eutectic microstructure yields significantly better tensile properties and an extremely high ductility of approx. 25% after solution heat treatment.

  ReaLizer SLM-100 machine[82]Li et al. ()AlSi10MgLaser power 200 W, hatch spacing 80 µm, laser spot diameter 80 µm, layer thickness 25 µm, exposure time 100&#;180 µs, point distance 60&#;100 µm.Modelling and simulation

  • A 3D FE model was developed to simulate the thermal behaviour and melt pool dimensions of the printed parts.

  • The cooling rate of the melt pool reduced from 7.93 × 106 °C/s to 3.61 × 106 °C/s as the laser exposure time is increased from 100 µs to 180 µs. Alternatively, with an increase in point distance from 60 µm to 100 µm, the cooling rate increased from 3.25 × 106 °C/s to 7.48 × 106 °C/s.

  • The melt pool size (width and depth) increased as the laser exposure time is increased, and vice-versa when the point distance is increased.

  Renishaw AM 400 SLM system (Renishaw PLC)[83]Li and Gu ()AlSi10MgLaser power of 150&#;300 W, laser spot diameter 70 µm, scanning speed 100&#;400 mm/s, layer thickness 50 µm, hatch spacing 50 µm, argon atmosphere.Modelling and simulation

  • SLM experimental results validated the obtained thermal behavior in simulation.

  • The cooling rate increased from 2.13 × 106 °C/s to 2.97 × 106 °C/s when the laser power was increased from 150 W to 300 W, and from 1.25 × 106 °C/s to 6.17 × 106 °C/s when the scan speed increased from 100 mm/s to 400 mm/s.

  • A sound metallurgical bonding between the neighboring layers was obtained at the optimized combination of process parameters, including laser power of 250 W and scan speed of 200 mm/s.

  YLR-500-SM[84]Liu et al. ()AlSi10MgLaser power 200 WTensile, hardness, density, roughness

  • An 80% decrease in surface roughness was observed when the printed parts were sand blasted.

  • The tensile properties of the as-built samples tested at both room temperature and high temperature (200 °C) are significantly better than the conventionally heat-treated cast parts.

  M2 Cusing from Concept Laser, Germany[85]Liu et al. ()AlSi10MgLaser power 500 W, scan speed mm/s, layer thickness 30 µm, zigzag scan strategy, scanning angle alternated by 90° for subsequent layers.Hardness, wear resistance, modelling and simulation

  • The cooling rate for the layers printed at the top region of the sample was determined to be about 1.44 × 106 K/s, which is significantly higher than that experienced by the bottom layers (&#; 1 × 103 K/s).

  • The top surface area has a lower degree of crystallinity of Al matrix than that of core area.

  • The surfaces of the printed samples exhibited higher hardness and wear resistance compared to the core regions.

  BLT-S300 SLM machine[86]Liu et al. ()AlSi10MgLaser power 160&#;200 W, spot size 100 µm, scanning speed 200&#; mm/s, argon atmosphere.Modelling and simulation

  • The cooling rate, temperature gradient and the solidification rate increase with an increase in laser power and decrease with an increase in scanning speed.

  • Along Z direction, the cooling rates and the temperature gradient are lower compared to Y direction.

  IPG YLR-200[87]Louvis et al. ()AA Laser power 50&#;100 W, laser spot size 80 µm, hatch spacing 0.05&#;0.3 mm, scan speed range 75&#; mm/s, layer thickness 50 µm, argon atmosphere, point distance 65&#;85 µmDensity

  • The formation of oxides can be avoided by using high laser powers while printing.

  • The maximum relative density was obtained at high laser power of 100 W (89.5%).

  MCP Realizer 100 SLM machine[8]Maamoun et al. ()AlSi10Mg & AA For AA : Laser power 300&#;370 W), scanning speed 800&#; mm/s, hatch spacing 0.1&#;0.19 mm, energy density 40.5&#;123.3 J/mm3.
  For AlSi10Mg: Laser power 200&#;370 W), scanning speed &#; mm/s, hatch spacing 0.15&#;0.25 mm, energy density 27&#;65 J/mm3. Tensile, hardness

  • The microstructure of AA parts did not show the same fibrous Si network that formed inside the AlSi10Mg microstructure due to lower Si content.

  • The size of the melt pool increases with an increase in energy density. An energy density range of 50 to 60 J/mm3 was found to be optimum to significantly minimize the formation of keyhole defects and porosities.

  • Maximum tensile strength of both the AlSi10Mg and AA printed samples was 396.5 MPa.

  -[88]Maconachie et al. ()AlSi10MgLaser power 350 W, scanning speed mm/s, layer thickness 30 µm, hatch spacing 130 µm and beam diameter 90 µm.
  Build Orientation: 0°, 45° and 90°. Tensile, dynamic behaviour in tension (SHTB), fracture

  • The tensile strength is not significantly affected by the build orientation of the printed samples.

  • Samples built perpendicular to the build direction failed at greater strain than those built parallel to the build direction.

  • The anisotropic properties of the samples were insensitive to the strain rate applied during mechanical testing.

  SLM500[89]Majeed et al. ()AlSi10MgLaser power 320 W, hatch spacing 0.08 mm, layer thickness 30 µm, scanning speed 900 mm/s, checkerboard scanning strategy, argon atmosphere.
  Heat Treatment: T4 treatment involving solution heat treated at 530 or 540 °C for 2 h and water quenched. T6 treatment involving solution treated at 530 °C for 2 h, water quenched and artificially aged at 155 °C for 12 h.Density, tensile, fracture

  • As the wall thickness increased from 0.5 mm to 1.5 mm, an increase in porosity was observed.

  • Ageing heat treatment resulted in better density of the thin wall samples.

  • The size of the pores increased till the wall thickness of 1.5 mm and then decreased with further increase in wall thickness.

  280 HL SLM[90]Maskery et al. ()AlSi10MgLaser power 200 W, layer thickness 25 µm, hatch spacing 130 µm, scanning speed 571 mm/s, point distance 80 µm, exposure time 140 µs, build platform temperature 180 °C, hatch rotation 67°.
  Heat treatment: Solution treated at 520 °C for 1 h, water quenched, and aged at 160 °C for 6 h.Tensile, fatigue

  • The elongation at break for the heat-treated material was nearly three times greater than that observed for the as-built material, and the fatigue strength at 106 cycles was around 1.6 times as high.

  • The UTS was reduced from 330 ± 10 MPa to 292 ± 4 MPa and the ductility enhanced from (1.4 ± 0.3)% to (3.9 ± 0.5)%.

  Renishaw AM250 SLM machine[91]Mfusi et al. ()AlSi10MgLaser power 150 W, scanning speed mm/s, hatch spacing 50 µm, and layer thickness 50 µm.
  Build Orientation: XY, 45°, and Z orientations.
  Heat treatment: Stress relief treatment at 300 °C for 2 h followed by furnace cooling.Tensile, fatigue crack growth, fracture toughness, density, hardness, porosity

  • Anisotropy due to different build orientations was found even after post stress relief heat treatment.

  • Maximum relative density was reported for XY printed samples (97.33 ± 0.92%). However, maximum hardness was reported for the 45° orientation printed samples (47.32 ± 3.35 HV).

  SLM Solution M280 GmbH[92]Ngnekou et al. ()AlSi10MgLaser powers 200 W and 400 W.
  Build Orientation: XY and Z
  Heat treatment: Stress relieved at 160 °C for 1 h or 300 °C for 2 h, T6 heat treatment involving solution treated at 540 °C for 8 h, water quenched, and tempered at either 20 °C for 24 h or 160 °C for 10 h.Fatigue

  • The improvement in fatigue resistance is less pronounced when large-sized defects are present in the printed samples.

  • There is no influence of the defect type on the fatigue limit.

  Phenix PM100 3D Systems machine
  EOS M290 machine [93]Nurel et al. ()AlSi10MgLaser power 400 W, spot diameter 80 µm, scan velocity mm/s, strip scanning strategy, hatch distance 200 µm, hatch rotation 67°, layer thickness 60 µm, argon atmosphere, build plate temperature 35 °C.
  Build orientation: Horizontal and Vertical
  Heat Treatment: T5/Stress relief treated at 300 °C for 2 h.Dynamic-Compression

  • The dynamic anisotropic properties were insensitive to variation in strain rates.

  • Anisotropic differences were considerably reduced by applying T5 heat treatment.

  • The as-built samples failed after SHPB tests which was observed in the T5 heat treated samples.

  EOSINT M280 system[94]Nurel et al. ()AlSi10MgLaser power 400 W, spot diameter 80 µm, layer thickness 30 µm.
  Build orientation: Horizontal and Vertical.
  Heat treatment: T5 at 300 °C for 2 h.Dynamic-Compression

  • No strain sensitivity was observed.

  • True stress for as-built and heat-treated conditions are 569 ± 8.5 MPa and 427 ± 4.8 MPa respectively.

  EOSINT M280 system[95]Ojha et al. ()AlSi10MgLaser power 100 W, scanning speed mm/s, spot size 0.2 mm, layer thickness 80 µm.Modelling and simulation

  • FEA was carried out to investigate temperature evolution, heat transfer and solidification process.

  • Simulation results are dependent on process parameters along with material properties.

  -[96]Pei et al. ()AlSi10MgLaser power 180 W, scanning speed 600&#; mm/s, layer thickness 35 µm, spot size 70 µm.Modelling and simulation

  • The perturbation or the instability within the molten pool results in the formation of pores during SLM, which have a direct influence on the densification level.

  • At high scanning speed, the track morphology became discontinuous leading to poor bonding and balling.

  SLM-150 equipment[97]Pola et al. ()AlSi10Mg-Fatigue, porosity, surface roughness, tensile

  • Post-treatment is effective in reducing surface roughness and inducing compressive residual stresses on the material surface.

  • Sand blasting had a beneficial effect of the fatigue resistance.

  EOS M290 system[98]Ponnusamy et al. ()AlSi12Laser power 285 W, scanning speed mm/s, hatch spacing 100 µm, layer thickness 40 µm, defocus distance &#;4 mm, alternative scan strategy.
  Build orientation: Horizontal, Inclined, VerticalDynamic - Compression

  • The dynamic compressive strength increased with an increase in the angle of print orientation, i.e., from 0° to 90°.

  • The yield strength and compressive strength decrease for printed samples tested at elevated temperature of 200 °C.

  • The flow stress was found to be higher for dynamic loading compared to quasi-static loading at elevated temperature.

  3D Systems ProX 200[99]Ponnusamy et al. ()AlSi12Laser power 285 W, scanning speed mm/s, hatch spacing 100 µm, layer thickness 40 µm, defocus distance &#;4 mm, alternative scan strategy, hexagon scan pattern, argon atmosphere.
  Build orientation: Vertical
  Heat treatment: Annealed at 200 °C and 400 °C for 3 hrs.Dynamic compression

  • Thermal softening was observed in printed samples tested at elevated temperatures, which resulted in significant reduction in flow stress.

  • A 20% and 50% reduction in flow stress was observed when samples were tested at 200 °C and 400 °C test temperatures, respectively.

  • A 12% and 45% reduction in flow stress was observed for samples heat treated at 200 °C and 400 °C, respectively, and then tested.

  ProX 200[100]Prashanth et al. ()AlSi12Laser power 320 W, layer thickness 50 µm, hatch spacing 110 µm, hatch rotation 73°, scanning speed &#; mm/s, argon atmosphere.
  Build orientation: 30°, 45°, 60°, 75°, 90°.
  Heat treatment: Solution treated at 473&#;723 K for 6 h.Wear rate, corrosion properties

  • As-built samples exhibit better wear resistance and similar corrosion resistance compared to cast counterparts.

  • Both wear and corrosion properties deteriorated with annealing post heat treatment, due to growth of Si precipitates.

  SLM 250 HL[16]Prashanth et al. ()AlSi12Laser power 320 W, layer thickness 50 µm, hatch spacing 110 µm, hatch rotation 73°, scanning speed &#; mm/s, argon atmosphere, scan strategies included single melt, double melt, single melt continuous, and checkerboard, base plate heating 473&#;673 K.
  Heat treatment: Solution treated at 473&#;723 K for 6 h.Tensile

  • The difference in tensile properties were attributed to the variation in crack propagation path.

  • The samples printed without contour exhibited significant increase in ductility without compromising on the tensile strength.

  • The results indicate that the room temperature tensile properties can be tuned (between YS: 115&#;290 MPa, UTS: 220&#;460 MPa and ductility: 2.8&#;9.5%) in-situ with appropriate selection of process parameters.

  SLM 250 HL[101]Prashanth et al. ()AlSi12Laser power 320 W, layer thickness 50 µm, hatch spacing 110 µm, hatch rotation 73°, scanning speed &#; mm/s, argon atmosphere.
  Build orientation: 30°, 45°, 60°, 75°, 90°.
  Heat treatment: Solution treated at 473&#;723 K for 6 h.Tensile

  • The Al and Si phases show remarkably small crystallite sizes of about 118 and 8 nm.

  • The as-built samples exhibited a yield strength of 260 MPa and tensile strength of 380 MPa, which was significantly higher than the cast counterparts.

  • The texture of the microstructure of the printed samples varied with variation in build orientations, however, this did not affect the tensile properties.

  SLM 250 HL[17]Qiu et al. ()AlSi10MgLaser power 150&#;400 W, beam spot size 50 µm, scanning speed &#; mm/s. Compression

  • The dimensions of the melt pool increased with an increase in laser power resulting in strut diameters deviating from the designed values.

  • The compressive load bearing capacity of the lattice structures increased with an increase in strut diameter.

  • Deformation of lattice structures occurred by homogeneous deformation until the maximum stress was achieved after which the structure lost structural integrity via a series of shear banding events at around 45° to the compression axis.

  Concept Laser M2 Cusing SLM system[102]Rakesh et al. ()AlSi10MgLaser beam diameter 80 µm, argon/nitrogen gas inert atmosphere.
  Build orientation: Transverse (XZ), Longitudinal (Y)Tensile, Impact strength

  • Printed samples displayed superior tensile strength (~350 MPa) and impact strength compared to cast parts.

  • Significant improvements in tensile properties and impact energies were observed in the transversely-built samples irrespective of the chamber atmosphere.

  EOSINT M280 machine[103]Rao et al. ()A357Laser power 100&#;370 W, layer thickness 30 µm, hatch distance 0.1 mm, spot size diameter 0.1 mm, scan speed 500&#; mm/s, substrate temperature 35&#;200 °C.
  Build orientation: Horizontal, Vertical.Tensile

  • The mechanical property was largely affected by different substrate temperatures.

  • The coarse Si precipitates formed along the build direction facilitates intercellular failure, resulting in poor tensile properties.

  EOSINT M280[25]Rao et al. ()A357Laser power 100&#;370 W, layer thickness 30 µm, hatch distance 0.1 mm, spot size diameter 0.1 mm, scan speed 500&#; mm/s, substrate temperature 35&#;200 °C.
  Heat treatment: Stress relieving at 300 ± 1 °C and air-cooled, solution treating at 535 ± 3 °C in salt bath from 0.25 h to 150 h followed by water quenching.Tensile

  • The as-built samples had an ultrafine microstructure, with high residual stresses and non-equilibrium solid solute concentration of Si in the supersaturated Al matrix.

  • The tensile properties of the printed A357 samples were comparable or better than the traditional cast counterparts.

  • The UTS and YS of as-built sample are 426.4 ± 2.6 MPa and 279.6 ± 1, respectively, however, the ductility was found to improve after stress-relieving (13.6 ± 0.6%).

  EOSINT M280[24]Rashid et al. ()AlSi12Laser power 285 W, scan speed &#; mm/s, layer thickness 40 µm, hatch distance 100 µm, defocus distance &#;4 mm.
  Build orientation: Horizontal, Inclined (45°), VerticalTensile, density

  • Energy per layer in the range of 504&#;895 J yielded &#; 99.8% relatively dense AlSi12 SLM-printed samples.

  • Yield strength range 225&#;263 MPa, tensile strength range 260&#;365 MPa, and ductility range 1&#;4% was found for the printed samples with different build orientations.

  • Anisotropy in mechanical properties was attributed to differences in relative densities.

  ProX 200[104]Rashid et al. ()AlSi12Laser power 285 W, scan speed &#; mm/s, layer thickness 40 µm, hatch distance 100 µm, defocus distance &#;4 mm.
  Lattice structures: Circular cells, honeycomb cells, triangular cellsFlexural

  • The printed samples exhibited brittle failure.

  • Triangular lattice structure had the highest flexural strength of 175.80 ± 1 MPa, circular 151.35 ± 0.67 MPa, and honeycomb 143.16 ± 3.85 MPa, whereas the solid specimen had a strength of 290 ± 26 MPa.

  • Triangular lattice structure showed good flexural modulus of 5 GPa compared to the honeycomb structure (4.34 GPa) and circular structure (4.37 GPa).

  ProX 200[105]Rathod et al. ()AlSi12Laser power 320 W, scan speed mm/s, layer thickness 50 µm, and hatch spacing 110 µm.Wear

  • Printed samples displayed significant anisotropy in wear rate due to change in laser track orientation.

  • Porosity significantly affected the wear rate.

  280HL equipment [106]Raus et al. ()AlSi10MgLaser spot size 80 µm, laser power 350 W, scan speed mm/s, layer thickness 30 µm, hatch distance 0.13 mm, stripe scanning strategy, argon atmosphere, build platform temperature 150 °C.Tensile, hardness, impact toughness

  • Porosities of the order of 5 to 20 µm were observed in relatively dense (99.13%) sample.

  • Printed samples displayed higher mechanical properties compared to high pressure die cast samples.

  SLM 125 HL[107]Read et al. ()AlSi10MgLaser power 100&#;200 W, laser track width 150 µm, layer thickness 30 µm, scan speed 700&#; mm/s, hatch spacing 0.2&#;0.8 mm, island scanning strategy, island size 2&#;8 mm, argon atmosphere.
  Build orientation: Horizontal, Vertical.Tensile, creep resistance

  • A critical energy density of 60 J/mm3 was found wherein minimum pore fraction was observed.

  • Creep results showed better rupture life than cast alloy, displaying good agreement with the Larson&#;Miller literature data.

  • Unmelted powder particles give rise to local cracking, as observed on the fracture surfaces.

  Concept Laser M2 Cusing SLM system[108]Rosenthal et al. ()AlSi10MgLaser power 400 W, laser spot size 100 µm, scan velocity mm/s, strip scanning strategy, hatch rotation 67°.Tensile, density

  • The mechanical properties of the printed parts displayed a strong dependency on the microstructure and are comparable or higher than cast part after T6 heat treatment.

  EOSINT M280[109]Rosenthal et al. ()AlSi10MgLaser power 400 W, laser spot size 100 µm, scan velocity mm/s, hatch distance 200 µm, layer thickness 60 µm, argon atmosphere.
  Build orientation: Horizontal (X), Vertical (Z).
  Heat Treatment: T5 stress relief treatment at 300 °C for 2 h, modified T5 at 200 °C for 2 h.Impact resistance

  • Horizontally built specimens absorbed more impact energy compared to vertically built specimens.

  EOSINT M280[110]Rosenthal and Stern ()AlSi10MgLaser power 400 W, laser spot size 100 µm, scan velocity mm/s, hatch distance 200 µm, layer thickness 60 µm.
  Heat treatment: Treated at 100&#;250 °C for 2 h, treated at 200 °C for 168 h, treated at 100 °C for 336 h.Hardness

  • Results revealed that the heat treatments conducted in the range of 100 °C&#;300 °C displayed noticeable increase in hardness values due to precipitation/coarsening of the Si phase.

  EOSINT M280[111]Rosenthal et al. ()AlSi10MgLaser power 400 W, scanning speed mm/s, strip scanning strategy
  Build orientation: Vertical, Horizontal.
  Heat treatment: Stress relieving at 300 °C for 2 h.Tensile, hardness, fracture morphology

  • The printed parts displayed room temperature mechanical properties comparable or even exceeding conventionally cast AlSi10Mg samples.

  • In the vertical orientation, the samples display Young&#;s modulus of 69.5 to 73 GPa, yield strength 167&#;170 MPa, UTS 269&#;277 MPa and elongation ranging 7.8&#;8.7%, whereas in the horizontal orientation Young&#;s Modulus ranges between 69&#;71.3 GPa, yield strength 168&#;170 MPa, UTS of 267 MPa and elongation ranging 8.6&#;9.5%.

  -[112]Rosenthal et al. ()AlSi10MgLaser power 400 W, laser spot size 100 µm, scan velocity mm/s, hatch distance 200 µm, layer thickness 60 µm, argon atmosphere, build plate temperature 35 °C, strip scanning strategy, hatch rotation 67°.
  Build orientation: Vertical, Horizontal.Tensile, fracture surface analysis

  • Printed samples were sensitive to strain rate variations with significant changes to the flow stress and strain hardening exponents with an increase in strain rate.

  • The strain rate sensitivity was similar in both vertical and horizontally printed samples, while the true strain was significantly higher in the samples built in the horizontal orientation.

  EOSINT M280[113]Samantaray et al. ()AlSi10MgLaser power ranging 70&#;190 W, laser spot diameter 0.2 mm, scanning speed 100&#;500 mm/s, layer thickness 1 mm.Modelling and simulation

  • The maximum temperature of the molten pool increased from 731 °C to °C and the molten pool length changed from 0.286 mm to 2.167 mm, when the laser power increased from 70 W to 190 W.

  • The sintering depth of the powder layer increased with an increase in laser power but decreased when the scan speed was increased.

  -[114]Siddique et al. ()AlSi12Laser power 400 W, volume energy density 39.6 J/mm3, argon atmosphere.
  Heat treatment: Stress relieving at 240 °C for 2 h followed by oven cooling.Fatigue, tensile

  • The microstructure of the printed samples consisted of fine grains and precipitates that resulted in increased quasi-static strength compared to that of the cast counterparts.

  • The fatigue strength of the as-built hybrid samples was comparably better than the as-built samples.

  SLM 250[115]Siddique et al. ()AlSi12Laser power 350 W, scan speed 930 mm/s, hatch distance 0.19&#;0.25 mm, energy density 20&#;39.6 J/mm3, argon atmosphere.
  Heat treatment: Stress relieving at 200 °C followed by oven cooling.Fatigue, porosity, modelling and simulation

  • Similar porosity percentage was found using optical microscopy and X-ray computed tomography techniques.

  • Hot isostatic pressing post treatment resulted in reduction of strength, however, was comparable to that of the die-cast parts.

  • Even smaller size pores present in the vicinity of the surface of the fatigue samples, significantly contributed to the decrease in fatigue life. This surface weakness effect was mitigated by the hot isostatic pressing post treatment.

  SLM 250 HL[116]Siddique et al. ()AlSi12Laser power 350 W, scan speed 930 mm/s, hatch spacing 0.19 mm, layer thickness 50 µm, energy density 39.6 J/mm3, scanning strategy chessboard, hatch rotation 79°, argon atmosphere, base plate temperature 200 °C.
  Build orientation: Vertical.
  Heat treatment: Stress relieving at 200 °C for 2 h.Fatigue, porosity, hardness, crack propagation testing

  • Stress relief post heat treatment at 240 °C caused an increase in porosity due to the growth of pores.

  • At low stresses, the samples printed with base plate heating displayed higher fatigue performance compared to the samples printed without base plate heating.

  • Samples printed without base plate heating consisted of higher porosity, which facilitated samples failing from cracking due to defects. Such an occurrence was significantly reduced in samples printed with base plate heating.

  SLM 250 HL[14]Siddique et al. ()AlSi12Laser power of 400 W, energy density 20&#;39.6 J/mm3, chessboard scanning strategy, hatch rotation 79°, argon atmosphere, base plate temperature 200 °C.
  Build orientation: Vertical.
  Heat treatment: Stress relieving at 240 °C followed by oven cooling.Tensile, surface roughness, residual stress analysis, fatigue

  • Base plate heating induces a coarser grain microstructure in the printed samples owing to a decrease in cooling rate.

  • Tensile strength of the printed samples was four times that of sand-cast parts and two times that of die-cast parts.

  • Significant reduction in residual stresses was observed in samples printed with base plate heating, which also reduced the scatter in fatigue data.

  SLM 250 HL[15]Silvestri et al. ()AlSi10MgEOS M400: Laser power W, laser spot diameter 90 µm, nitrogen atmosphere.
  SLM 280: Laser power 400&#; W, laser spot diameter 80&#;225 µm, argon atmosphere.
  Renishaw AM400: Laser power 400 W, laser spot diameter 70 µm, argon atmosphere.
  Build orientation: 0°, 60°, 90°.Tensile

  • The mechanical properties of the samples printed using different SLM machines were different, even though the best process parameters suggested by the equipment manufacturers were employed.

  EOS M400
  SLM 280
  Renishaw AM400[117]Subbiah et al. ()AlSi10MgLaser power 350 W, laser spot size 0.2 mm, scanning speed 730 mm/s, hatch spacing 0.12 mm, layer thickness 30 µm, stripe scanning strategy, inert atmosphere, base plate temperature 150 °C.
  Heat treatment: Solution treated at 550 °C for 2 h and water quenched.Tensile, surface roughness, modelling and simulation

  • The microstructural studies revealed that the samples were stretched due to the exclusion of Si enriched cellular and dendritic network.

  • Printed samples exhibited high tensile strength of 431 MPa.

  SLM 280 HL[118]Sun et al. ()AlSi10MgLaser power 400 W, laser spot size 100 µm, scanning speed mm/s, hatch spacing 0.165 mm, layer thickness 25 µm, chessboard scanning strategy, hatch rotation 67°.
  Heat Treatment: T2 treatment&#;annealed at 380 °C for 45 mins and air cooled, T6-like treatment&#;solution treated at 500 °C for 15 mins, quenched, and aged at 158 °C for 10 mins.Tensile

  • A homogeneous distribution of spheroidised Si was observed in heat treated parts.

  • It was suspected that Si experienced the necking effect under a tensile environment due to the large temperature gradient and α-Al erosion during the SLM process.

  • The tensile strength of the as-built samples was better than the as-cast samples, however, the strength reduced with subsequent post heat treatment.

  Renishaw AM 250[119]Suryawanshi et al. ()AlSi12Laser power 320 W, layer thickness 50 µm, hatch spacing 110 µm, hatch rotation 73°, scanning speed ( mm/s for volume and mm/s for contour), argon atmosphere, single melt and checkerboard scanning strategy.
  Heat treatment: solution treated at 573 K for 6 h.Tensile, fracture toughness, fatigue crack growth

  • The fatigue crack growth threshold and unnotched fatigue strength of SLM alloys was inferior compared to cast alloys, which could be attributed to tensile residual stresses, shrinkage porosity, and un-melted particles.

  • The printed samples exhibited enhanced toughness due to the presence of mesostructure Si.

  • Toughness was found to be sensitive to crack orientation with respect to the build and scan orientations.

  SLM 250 HL[120]Takata et al. ()AlSi10MgLaser power 380 W, layer thickness 30 µm, hatch spacing 0.1 mm, hatch rotation 67°, argon atmosphere.
  Build orientation: Horizontal (X/Y), Vertical (Z).
  Heat treatment: Annealing at 300 °C for 2 h, or solution treatment at 530 °C for 6 h and water quenched.Tensile

  • A fine dislocation substructure consisting of low angle boundaries was found within the α-Al grains.

  • {001} texture along the Z direction was observed which was attributed to the preferential <001> grain growth of the α-Al phase during rapid solidification.

  • The as-built samples exhibited a high tensile strength of approximately 480 MPa irrespective of the build orientation. In contrast, the ductility was direction-dependent, thereby resulting in the fracture preferentially occurring at the melt pool boundaries.

  EOSINT M 280[121]Tang and Pistorius ()AlSi10MgLaser power 370 W, scan speed mm/s, layer thickness 30 µm, laser spot diameter 100 µm, hatch spacing 0.16&#;0.22 mm, hatch rotation 67°.
  Build orientation: XY, Z.
  Heat treatment: Stress relieving at 573 K for 2 h.Tensile, fracture morphology, porosity

  • The Z-oriented samples flow at a lower imposed stress than the XY-oriented samples.

  • The maximum yield strength was noted for the XY-built samples, while maximum tensile strength was observed for the Z-built samples.

  • Variation in hatch spacing results in porosity formation in the printed parts, which subsequently reduced the tensile performance.

  EOS M280[122]Tang and Pistorius ()AlSi10MgLaser power 370 W, scan speed mm/s, laser beam diameter 0.1 mm, layer thickness 30 µm, hatch spacing 0.16&#;0.22 mm, and the
  Build orientation: XY, Z.
  Heat treatment: Stress relieving at 573 K for 2 h.Fatigue, porosity

  • A correlation between the crack-initiating pore on the fracture surface and fatigue life was established.

  • The fatigue resistance was affected by the variation in hatch spacing and build orientation.

  • XY-oriented samples have better fatigue performance, possibly due to anisotropy of pores, residual stress, and of melt-pool boundaries.

  EOS M280[123]Tradowsky et al. ()AlSi10MgLaser power 175 W, laser spot size 60 µm, scan speed mm/s, layer thickness 30 µm, scan spacing 97.5 µm, chess scanning strategy, island size 5.6 mm, argon atmosphere.
  Build orientation: Horizontal, Vertical.
  Heat treatment: Solution treated at 520 °C for 5 h, water quenched, and aged at 160 °C for 12 h followed by air cooling.Tensile, porosity, modelling and simulation

  • Columnar grains were observed along building direction, with equiaxed grains found in-cross section.

  • Irregular-shaped voids were observed in both the as-built and heat-treated conditions due to the formation of oxide layer. These pores were considerably reduced after hot isostatic pressing post treatment, however, the oxide layers remained.

  • Heat treated and hot isostatic pressed samples had tensile properties exceeding that of the cast counterparts.

  Concept Laser M2 cusing system[124]Trevisan et al. ()A357Laser power 195 W, spot size 100 µm, layer thickness 30 µm, scanning speed mm/s, hatch distance 0.1 mm, hatch rotation 67°, build plate temperature 100 °C.
  Heat treatment: Stress relieving at 300 °C for 2 h, T6 treatment involving solution treatment at 540 °C for 8 h, water quench, and ageing at 170 °C for 3 h.Tensile, hardness

  • The tensile strength decreased after stress relief heat treatment.

  • After T6 heat treatment, the microstructure became more isotropic, and the mechanical properties were comparable to that of the as-built condition.

  EOSINT M270 Dual mode machine[125]Uzan et al. ()AlSi10MgLaser power 400 W, beam diameter 100&#;150 µm, scanning speed mm/s, layer thickness 30 µm and 60 µm (before and after melting), hatch distance 200 µm, stripe scanning strategy, argon atmosphere, build plate temperature 35 °C.
  Build orientation: Z direction.
  Heat treatment: Stress relieved at 300 °C for 2 h.Fatigue, tensile, fracture toughness, hardness

  • The fatigue resistance of the as-built samples was highest and that of the stress relieved and hot isostatic pressed samples was the lowest.

  • The critical stress intensity factor can be estimated by the fracture surface morphology of the fatigue specimen.

  EOSINT M-280 [126]Vrana et al. ()AlSi10MgLaser power 150&#;400 W, layer thickness 50 µm, scanning speed &#; mm/s, nitrogen atmosphere, build platform temperature 120 °C.Impact testing

  • Lattice structures fabricated with scanning speed of 500 mm/s achieved 10× higher stiffness than those printed using mm/s for the same geometry of the unit-cell.

  • Samples printed with a laser power of 350 W and scanning speed of mm/s achieve greater geometrical stability and had better accuracy.

  SLM 280HL[127]Wang et al. ()AlSi10MgLaser power 370 W, scan speed mm/s, hatch spacing 190 µm, layer thickness 30 µm, argon atmosphere.
  Build orientation: Vertical.
  Heat treatment: Stress relieved at 250 °C for 4 h.Tensile, porosity, modelling and simulation

  • The deviation between reconstructed and as-designed models was less than 100 μm.

  • The anisotropic properties of the printed parts were attributed to the non-uniform distribution of process-induced defects within the samples, which had a deleterious effect on the tensile strength.

  • The presence of geometric defects significantly influenced the tensile strength and elongation.

  EOS M290[128]Wang et al. ()AlSi10MgLaser power 400 W, laser spot size 76 µm, scanning speed mm/s, hatch distance 175 µm, layer thickness 25 µm, chessboard scanning strategy, island size 5 mm, argon atmosphere.
  Heat treatment: T6 solution treated at 535 °C for 7&#;15 mins and aged at 158 °C for 10 h.Tensile, bending, hardness

  • A decrease of about 20% in hardness and tensile strength whereas an increase of about 155% in elongation was reported for the heat-treated samples.

  • An increase of about 123% in fracture deflection and a decrease of about 6% in bending strength was also found for the heat-treated samples.

  Renishaw AM 250[129]Wang et al. ()AlSi10MgLaser power 400 W, scanning speed mm/s, hatch spacing 175 µm, layer thickness 25 µm, chessboard scanning strategy, hatch rotation 67°.
  Build orientation: Parallel, Normal.
  Heat Treatment: T2 stress relieving treatment at 380 °C for 45 mins followed by air cooling.Tensile, bending, hardness

  • The hardness, tensile strength and bending strength decrease by about 50% after T2 heat treatment

  • The precipitates in the molten pool boundaries dissolve in the matrix after heat treatment.

  Renishaw AM 250 system[130]Wang et al. ()AlSi12Laser power 200 W, beam diameter 35 µm, scanning speed 375&#; mm/s, hatch spacing 0.15 mm, layer thickness 50 µm, stripe scanning strategy, hatch rotation 90°, inert atmosphere.Tensile, hardness

  • Insignificant differences in density and hardness was observed when the samples were printed in either argon, nitrogen, or helium chamber atmospheres.

  • The samples showed superior performance; 1.5 times yield strength, 20% higher tensile strength, and twice elongation, compared to conventionally produced material.

  Realizer SLM 100[131]Wei et al. ()AlSi10MgLaser spot size 70 µm, laser power 150&#;180 W, scanning speed 600&#; mm/s, layer thickness 40 µm, hatch spacing 50&#;70 µm, random scanning strategy, argon atmosphere.Tensile, fracture morphology

  • A linear energy density of 1.5&#;1.875 J/cm was reported to yield continuous single-track depositions.

  • The level of porosity was significantly influenced by the variation in hatch spacing.

  • The pores and un-melted particles cause reduction in tensile strength and strain.

  Self-developed SLM 150 equipment[132]Wu et al. ()AlSi10MgLaser power 175 W, scanning speed mm/s, hatch spacing 0.65 mm, island size 6 mm.Tensile, in-situ compression testing

  • Long cell-like structures are formed in the printed samples owing to the high cooling rate of the process.

  • The Al within the eutectic grows epitaxially on the pre-existing Al cell resulting in further epitaxial growth of the Al cell formed above the eutectic.

  • Si precipitates present across the Al-matrix inhibits dislocation motion within the large Al grains.

  Concept Laser M2 system[133]Yan et al. ()AlSi10MgLaser beam diameter 100 µm, laser power of 400 W, layer thickness 30 µm, argon atmosphere.Compression, computed tomography

  • Lattices with cell sizes 3&#;6.5 mm were very thin for a low volume fraction of 5%, which tended to break during printing.

  • The printed samples showed good geometric agreement with the CAD model.

  • The compressive modulus and strength of the printed samples directly proportional to the volume fraction of the lattice cells and inversely proportional to the unit cell sizes.

  EOSINT M280[134]Yang et al. ()A357Laser power 750 W, scanning speed mm/s, hatch rotation 90°, build plate temperature 35 °C.
  Build orientation: Horizontal, Vertical.
  Heat Treatment: Directly aged at 160 °C for 8 h; Stress-relieved at 300 °C for 2 h; Stress-relieved and solution treated at 543 °C for 1&#;8 h, quenched and aged at 160 °C for 8 h.Tensile, porosity

  • Anisotropy in ductility between horizontally and vertically built samples decrease with solution heat treatments carried out for longer periods of time.

  • Negligible coarsening of the columnar grains was observed for all heat treatment conditions.

  • The stress relieved sample displayed highest elongation to fracture, primarily owing to the break-up of the Si network into fully dispersed Si particles.

  Concept Laser X-line machine[26]Zaretsky et al. ()AlSi10MgBuild orientation: XY, Z.
  Heat treatment: T5 stress relieving at 300 °C for 2 h.Dynamic and quasi-static tensile

  • Fracture of the printed samples at different tensile rates reflect a change in fracture mode from rate-independent ductile mode to rate-dependent brittle mode.

  • At high plastic strain rate range, the yield strength of the printed samples was strain rate sensitive.

  EOSINT M280 system[135]Zhang et al. ()AlSi10MgLaser power 490 W, scanning speed mm/s, layer thickness 40 µm, hatch spacing 0.1 mm, hatch rotation 90°, argon atmosphere.
  Heat treatment: Stress relieved at 300 °C for 2 h; Solution treated at 530 °C for h, water quenched, and aged at 170 °C for 12 h. Fatigue, tensile

  • Heat treatment reduces fatigue property due to the coarsening of Si precipitates.

  • For most of the fractured surfaces, the crack initiation sites indicated a presence of surface or subsurface defects.

  • The as-built samples display higher fatigue property compared to heat treated samples.

  Self-developed SLM system (LSNF-2)[136]Zhou et al. ()AlSi10MgLaser power 400 W, scanning speed mm/s, layer thickness 30 µm, hatch spacing 0.19 mm.
  Heat treatment: T6 solution treated at 520 °C for 0.5&#;4 h, water quenched, and aged at 160 °C for 1&#;24 h.Hardness

  • Eutectic structure up to 4 μm in size containing tiny needle-like semi-coherent Si particles were observed within the Al cells.

  • Embedded spherical nanoscale Si particles and segregated Mg and Fe were observed along the cell and grain boundaries of primary Al. The π-Al8Si6Mg3Fe precipitates were also identified along the boundaries.

  • Peak hardening was observed after ageing at 160 °C for 6&#;10 h, and remained relatively unchanged up to 24 h treatment time.

  EOS M280[137]Zhou et al. ()AlSi10MgLaser power 300 W, scanning speed 800 mm/s, laser spot size 80 µm, hatch spacing 0.13 mm, layer thickness 30 µm, volumetric energy density 62.5 J/mm3, argon atmosphere, build plate temperature 150 °C.
  Heat treatment: Stress relieved at 300 °C for 2 h and water quenched; solution treated 535 °C for 1 h, water quenched, and aged at 190 °C for 10 h.Tensile

  • Stress relieving post heat treatment was effective for eliminating residual stresses.

  • The printed samples exhibited tensile strength of 273.2 MPa and plasticity of 15.3%.

  SLM 280 HL[138]

  Understanding die casting

  Understanding die casting

  From engine blocks to door handles, die casting is a fast, accurate, and repeatable metal production technique suitable for large or small parts. Die casting parts have an excellent surface finish, and the process is compatible with a range of non-ferrous metals.

  Because of the high startup costs associated with die casting, the process is typically used for high-volume production, where the scale of manufacturing makes up for the high machinery and tooling costs. Die cast prototypes and low-volume production runs are harder to obtain, as it is in the economic interests of die casting companies to work with customers placing bulk orders. However, 3ERP currently provides a unique die casting solution for customers wishing to place smaller die casting orders.

  This article takes an in-depth look at metal die casting, explaining the suitable materials, surface finishes, and applications for the process.

   

  What is die casting?

  Die casting is a type of metal casting that uses high pressure to force molten metal into a mold cavity formed by two dies. It shares traits with the plastic manufacturing process of injection molding.

  Within the larger metal casting landscape, die casting is one of the most popular techniques due to its accuracy, high quality, and level of detail. The broader category of metal casting, which has existed for thousands of years, contains many different processes that use a mold to form liquid metal. Historically, such a process usually involved pouring the liquid metal into the mold with the aid of gravity &#; and many metal casting processes still work this way. Die casting, however, is a relatively new form of metal casting, introduced in the 19th century, and it uses pressure instead of gravity to fill the mold cavity.

  Die casting is sometimes called high-pressure die casting, due to the amount of pressure &#; typically 10&#;140 megapascals &#; used to force the metal into the mold cavity. The related process of low-pressure die casting (LPDC) is less common. Die casting typically falls into one of two categories: hot-chamber die casting and cold-chamber die casting, which are suitable for different types of metal. However, there are also other more niche types of die casting, such as semi-solid metal casting (SSM).

   

  Cast Aluminum: Everything You Need to Know

  Cast aluminum is a specific aluminum that is formed by casting technique. There is a wide application of cast aluminum due to its lightweight yet good strength. Cast aluminum could be seen in both daily life and industrial applications, such as cast aluminum cookware, cast aluminum chair legs, cast aluminum pumps, and more.

  As a professional casting company, we can produce custom cast aluminum parts following your drawing&#;s specifications. There are several aluminum casting processes available at our foundry, including aluminum die casting, aluminum gravity casting and aluminum sand casting. Each casting process has its special advantages, and we can recommend a best suitable casting process according to the design of the aluminum part.

  What is Cast Aluminum?

   

  Cast aluminum refers to aluminum that has been heated to its melting point before pouring it into molds for specific shapes or forms. The casting process involves heating aluminum until its melting point has been reached, then pouring it in an appropriate mold where it cools and solidifies to produce desired forms or shapes. After casting, post operations such as trimming and surface grinding are performed to achieve net shape castings.

  Benefits of Cast Aluminum

  Cast aluminum, particularly from manufacturers, offers a range of benefits for various applications. Here&#;s a closer look at the advantages of cast aluminum:

  Complex Design Capability

  Cast aluminum has its ability to creat parts into complex shapes, no matter how intricate the design is. For its excellent fluidity of aluminum alloys, thet can fill mold cavities completely, and an exact solid cast piece is formed after solidification. 

  Lightweight Yet Strong

  Aluminum is known for its high strength-to-weight ratio. Parts made from cast aluminum can provide the required strength for great working performace, while maintaning light weig

  ht part. This is not available when parts made from other casting materials such as cast steel or cast iron. This benefit makes cast aluminum a good application especially for automotive and aerospace industries.

  Excellent Corrosion Resistance

  When exposed to atmospheric conditions, aluminum can naturally form an oxide layer, this protects it against corrosion. So, after casting, cast aluminum parts have excellent corrosion resistance, which make them an ideal choice in harsh or corrosive environments, like marine applications or outdoor furniture. If there is a higher requirement, cast aluminum parts could be further anodized or powder painted to improve its enchace its corrosion resistance capacity.

  Faster Speed of Production

  The casting process of aluminum parts is always faster than other manufacturing process, such as machining or welding fabrication process. As most of the aluminum casting processes are automated, once the molds are prepared, the production process of cast aluminum parts is very fast. Cast aluminum can provide shorter lead times while high quality products.

  Cost-effectiveness for Manufacturing

  Even with an intial investment in mold, due to the great production speed and less material waste, the cost per cast aluminum part is very economical. Besides, cast aluminum has the ability to creat a simple piece in complex shapes, and reduce or remove the need for post machining, which lower the production cost in further step.

  The Casting Processes for Aluminum

   

  1. Low / High Pressure Die Casting

  Low Pressure Die Casting (LPDC) is the casting process that can produce cast aluminum parts at low pressure, typically between 20 psi and 100 psi. In this process, aluminum is melted and then tranferred into a mold under low pressure until the aluminum solidifies. Cast aluminum parts made from this process can achieve good dimensional accuracy even in medium to high volumes. It is particularly suitable for making cast aluminum parts in thicker wall thickness.

  High Pressure Die Casting (HPDC), as its name implies, creats cast caluminum parts at high pressure, typically between 10,000 and 15,000 psi. In this process, molten aluminum is injected into a mold under high pressure fastly. By high pressure die casting, thin-walled cast aluminum parts with complex shapes could be made. Besides, it also allows for high volume production. The strength of cast aluminum made in this process is the best among all the aluminum casting processes.

  2. Gravity Die Casting

  Gravity Die Casting, sometimes referred to as permanent mold casting, involves pouring molten aluminum into metal molds using gravity for permanent cast aluminum production. Molds made of steel or cast iron typically can support useable multiple cycles, which make gravity die casting an economical medium-to-high volume production method. Cast aluminum parts made from this process can achieve improved mechanical properties and finer surface finishes than sand casting method.

  3. Sand Casting

  As one of the most versatile casting processes available today, sand casting is not limited to make cast steel and cast iron parts, it can creat cast aluminum parts as well. Cast aluminum parts with intricate geometries are usually made in sand casting process, which is challenging by other casting methods. Aluminum sand casting process involves creating a mold from sand mixture, then pouring molten aluminum into it for solification. Next, the mold is broken away to take out the finished cast aluminum part. This process prpvides flexibility on mold design, so it supports both small and large cast aluminum parts with intricate shapes. While the surface is rougher when compared with die casting process.

  Common Cast Aluminum Alloys

   

  Because of the excellent mechanical properties and casting ability, cast aluminum is widely used by many industries. At Foundry, we have the capability to produce cast aluminum parts in different alloys, including A356, A360, A380, A383. They have unique chemical compositions, each alloy shows district advantages for different applications.

  A356 Aluminum Alloy

  A356 aluminum alloy is the most common material in aluminum gravity casting. The T6 heat treatment can further improve its strength and will be helpful for machining operation. The main chemical elements of A356 alloy include aluminum, magnesium (0.02-0.45%), silicon (6.5-7.5%) and other elements. Due to its good castability, welding ability and corrosion resistance, it is widely used in aluminum gravity casting process to creat parts with high strength and ductility. A356 castings are widely used in automotive and aerospace applications, as well as other industries.

  A360 Aluminum Alloy

  The A360 aluminum alloy mainlt consists of elements like aluminum, magnesium (0.4-0.6%), silicon (9-10%) and copper (6%). These compositions increases its strength and corrosion resistance when compared to other metals. A360 can offer good pressure tightness, which is critical for fluid-handling components. The excellent castability of A360 and its aesthetic surface finish makes it a good choice for casting housings, connectors and complex automotive components.

  A380 Aluminum Alloy

  A380 is a widely used cast aluminum alloy that contains aluminum, silicon (7.5-9.5%), copper (3-4%) and other elements such as iron, nickel and zinc. It is a versatile die casting material due to its high thermal conductivity and fluidity.

  A383 Aluminum Alloy (ADC12)

  A383, also known as ADC12, is also a common die cast aluminum alloy. Its composition differences can improve its casting characteristics when compared with A380 alloy. This alloy includes elements like copper, silicon, and aluminum (9.5-11.5%).

  How To Select a Right Casting Process for Aluminum?

  When selecting a right casting process for aluminum parts, it is necessary to evaluate both the usage of the part and the material properties of cast aluminum alloy. 

  Design Complexity

  The complexity and detail of any design play an essential part in selecting an optimal casting process. High-pressure die casting specialises in producing parts with intricate geometries and tight tolerances, making it ideal for creating aluminum parts with fine details and high accuracy. So, when the cast aluminum parts have a high requirement on dimensional accuracy and surface finish, high pressure die casting is the best choice for high volume production. For simpler or thicker designed parts, gravity die casting or sand casting may offer more cost effective solutions. Besides, sand casting is also suitable for large cast aluminum parts in small volume production.

  Production Volume

  Production volumes is also a necessary consideration factor for cast aluminum parts production. For high-pressure die casting, it is only cost effective for high volume production runs due to its high investment on the mold cost. Of course, it is worth to mention that the production efficiency is also very high. Medium volume projects might consider gravity die casting. While for low and prototype runs, sand casting may offer advantages due to reduced tooling costs, although its per-unit costs are higher.

  Material Properties and Performance

  For its superior strength-to-weight ratio and corrosion resistance of aluminum alloys, they are widely used in casting production. Casting process will further affect the properties. For example, high pressure die casting creates denser microstructures which enhance mechanical properties but increase porosity. Gravity die casting provides excellent material integrity which makes this approach ideal for moderate strength applications. While sand casting produces coarser microstructures which may result in parts with lower mechanical properties than expected &#; it is therefore vital that we clearly establish any performance expectations before choosing this form of casting as our final solution!

  Surface Finish

  The surface finish is also an important factor to consider when selecting an aluminum casting process. High pressure die casting can provide the finest surface quality of cast aluminum parts, and less or no machining is needed after casting. Low pressure die casting sand gravity die casting also offer good surface finish after fine blasting. While sand casting often provides rougher surface finish, which usually need further machining to achieve higher surface finish.

  Cost Considerations

  Cost factor could not be ignored when selecting a casting process for aluminum parts. High pressure die casting has the advantages of speed, precision and surface finish, but it requires a high tooling investment, and is more ideal for large orders. Gravity die casing and low pressure die casting offer lower tooling cost, but its unit cost is relatively higher. Sand casting is a most econimical selection for low volume production, while its unit cost per part is the highest when compared with other casting processes, and additional machining operation is usually required for closer tolerances or higher surface finish.

  Cast Aluminum vs. Forged Aluminum

  The fundamental difference between Cast and forged aluminum is easy to understand: Cast aluminum is the aluminum that was melted in a furnace and poured into a mold. Forged aluminum is when the metal is worked in the solid form with the help of specific tools. These two manufacturing processes will yield two materials with very different properties.

  Aluminum has a wide range of uses across every major industry, however, it is often difficult to decide which grade is best suited to a specific application. The challenge becomes greater when comparing not only between alloys but also between cast and forged aluminum. Both are fundamentally aluminum alloys which often have the same alloying elements but in different compositions and quantities. However, the applications and material properties vary widely between the two.

  Examples of Cast Aluminum Products

   

  You may be surprised to find out that many of the commercial products you come in contact with every day may be using cast aluminum parts and components or even be made entirely from cast aluminum.

  Car Parts

  Due to the amazing strength and light weight of cast aluminum parts, it is very popular in the production of car parts. For example, safety-critical parts like airbag housings or seat-belt retractor spools are made with diecast aluminum. In addition, steering knuckles, which support the wheel bearing, are made with this material. This is an essential part of a vehicle&#;s suspension, so the lightweight material helps to reduce the overall weight of the car without compromising strength or performance.

  Lighting Parts

  Due to the light weight and good corrosion resistance of cast aluminum, it is always used as the casting alloy for various lighting parts. Cast aluminum lighting parts could be designed and produced by either gravity die casting or high pressure die casting process.

  Medical Devices

  Many medical devices are also made from cast aluminum, not only due to the strength but also due to its heat resistance. Some of the more common medical equipment you may see made from this metal is parts for various pumps, surgical tools, components for monitors, and even gearboxes for hospital beds.

  Firearms

  Another popular application for die casting is the production of firearms. While many popular firearms may have plastic components, there are still a number of parts that are created from die-cast metals. Some of these parts may include triggers, trigger guards, trigger safetys, and much more.

  Cast Aluminum Cookware

  For decades, cast aluminum cookware (flater beater, dough hook, etc)  has been a vital tool in a well-stocked home kitchen. The versatile product is perfectly suited for cooking on the stovetop and baking in the over. It is dishwasher safe, making for a quick and easy clean up. Despite some ridiculous reports, it is safe to use for cooking and poses no health risks at all.

  If you&#;re looking for pots and pans made from this material, the good news is they&#;re everywhere. You can find brand-new sets on the websites of major retailers. If a more classic style is what you are after, you can even find vintage cast cookware on eBay.

  Cast Aluminum Patio Furniture

  When you think about investing in patio furniture you want something attractive, durable, and low-maintenance. If you also want an outdoor ensemble that&#;s available in a variety of styles, finishes, and colors, cast aluminum patio furniture including cast aluminum chair legs may provide you with an ideal setting to enjoy entertaining and relaxing with family and friends.

   

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• Heat treating the samples significantly improved the fatigue life, and it was found that at 94 MPa stress loading, the heat-treated samples outperformed their cast counterparts in terms of fatigue life.

• The samples that were heat-treated and machined showed the best fatigue performance.

Renishaw AM250[27]Aboulkhair et al. ()AlSi10MgLaser power 200 W, scan speed 550 mm/s, hatch spacing 130 µm, layer thickness 25 µm, and checkerboard scan strategy.
Heat treatment: T6Tensile strength, compressive yield strength, nano-hardness

• The printed parts had tensile strength better than the diecast parts.

• After heat treatment, the hardness and the tensile strength of the printed parts reduced by about 20% and 12%, respectively, whereas the ductility increased by a factor of 2.8.

• The compressive yield strength of the heat-treated parts was 169 ± 6 MPa which was approximately half the strength of the as-built parts.

Renishaw AM250[11]Aboulkhair et al. ()AlSi10MgLaser power 200 W, point distance 80 µm, exposure time 140 µs, hatch spacing 130 µm, layer thickness 25 µm and checkerboard scan strategy.Tensile and compressive strength, nano-hardness

• Uniform nano-hardness of 1.82 ± 0.01 GPa was observed in the SLMed samples due to the homogeneous distribution of Si particles segregating at α-Al grain boundaries.

• Microhardness along the plane parallel to the build plane was found to be higher (109.7 ± 0.9 HV) than the plane perpendicular to the build plane (99.07 ± 2 HV).

Renishaw AM250[12]Alghamdi and Haghshenas ()AlSi10MgTwo 400 W lasers at CalRAM Inc. were used, with default SLM 280 parameter set.
Heat Treatment: T6, solutionising at 520 °C for 1 h, followed by water quench, then artificial ageing at 170 °C for 4 h.Nano-hardness

• The nano-hardness of the heat-treated samples (1.56 ± 0.11 GPa) was reduced by 42% compared to the strength of the as-built samples (2.71 ± 0.12 GPa).

• Heat treatment of the samples resulted in the change in microstructure from cellular grains to fragmented/spheroidised eutectic silicon particles.

• The effect of the indentation size was observed in both as-built and heat-treated samples. With the decrease in the depth of indent, the hardness increased.

400 W laser at CalRAM Inc.
SLM 280[28]Amani et al. ()AlSi10MgLaser power 250 W, scanning speed 571 mm/s, layer thickness 60 µm, and argon gas atmosphere.Compression behaviour

• Deformation behaviour of two face-centred cubic lattice structures with thin and thick struts was studied using both in-situ and ex-situ X-ray computed tomography technique.

• A finite element model was developed using Gurson-Tvergaard-Needleman (GTN) porous plasticity model.

• Simulations showed a fairly good agreement with the model&#;s prediction of fracture location.

SLM 250[29]Anwar & Pham ()AlSi10MgLaser power 350 W, layer thickness 100 µm, laser speed 900 mm/s, and hatch spacing of 0.12 mm.Tensile strength

• The quality of the as-built samples depended upon the velocity of the gas flow in the built chamber, the direction of laser scan with respect to the gas flow direction, and position of the part with respect to the chamber outlet location.

• Higher ultimate tensile strength (UTS) values for parts printed with laser scan direction against the gas flow, with higher gas velocity, and closer to the outlet was observed.

• When the laser scanning was in the direction of gas flow, a reduced accumulation of spatter powder particles was observed near the outlet.

SLM Solutions 280 HL[30]Asgari et al. ()AlSi10MgLaser power 370 W, scanning speed mm/s, hatch distance 190 µm, powder layer thickness 30 µm, build platform pre-heating temperature 200 °C.
Build orientation: Vertical and Horizontal.Dynamic compression, Split Hopkinson pressure bar testing

• Increasing the strain rate from 150 s&#;1 to s&#;1 resulted in higher yield, peak flow stress, and ductility.

• The texture evolution could be attributed to vertical build orientation than horizontal build orientation due to uniform and dense microstructure, while the texture is not affected by the deformation at high strain rates.

EOS M290 machine [31]Aversa et al. ()A357Laser power 195 W, scan speed mm/s, layer thickness 30 µm, hatching distance 0.1 mm and stripe scanning strategy.Tensile

• Effect of build plate heating on the tensile properties was evaluated and build plate heating temperatures of 140 °C and 170 °C were reported to yield highest tensile strength of 408 ± 5 MPa and a yield strength of 284 ± 3 MPa.

• The platform heating induces artificial ageing within the print-parts during processing.

• Low platform heating temperatures result in under-ageing whereas high platform heating temperatures result in over-ageing of the printed samples.

EOS M270 Dual Mode system[32]Awd et al. ()AlSi10MgProcess parameters not disclosed.
Build orientation: 0°, 45° and 90° with respect to the build plate.Tensile

• The pore density of 90° built samples were seven times higher than the 0° built samples.

• The 0° built samples displayed 8% higher tensile strength than the samples built at 90° orientation.

• Samples fabricated along the 45° orientation had a significantly reduced fracture strain.

M2 Cusing system[33]Baitimerov et al. ()AlSi12Laser power 200 W, layer thickness 50 µm, stripe hatch scanning strategy, powder dried at 100 °C for 1 h and the oxygen inside the build chamber was maintained below 500 ppm.Density

• Using the optimised process parameters, a relative density > 99% was achieved.

• The AlSi12 powder with good flowability and apparent density leads to good processability in SLM, while highly fine and spherically shaped powder particles result in poor processability.

• The particles with nearly spherical shaped morphology exhibited very poor flowability, leading to high porosity levels.

Sinterstation® Pro DM125 SLM System[34]Bao et al. ()AlSi10MgLaser power ranging 360 W&#;400 W, layer thickness 0.05 mm, laser scanning speed mm/s&#; mm/s, scan spacing 0.13&#;0.16 mm.Fatigue

• The cyclic plasticity occurs when the longitudinal strain exceeds 0.9.

• The failure of the printed parts was attributed to the presence of large density of secondary micro-voids.

• The elongation of original defects along the loading direction is 10 times faster than that along the lateral side.

BLT S310[35]Bassoli et al. ()A357Laser power 950 W, scan speed mm/s, spot size 400 µm, hatch distance 0.2 mm, layer thickness 50 µm, nitrogen gas chamber atmosphere, preheating temperature 200 °C and skin core scan strategy.Tensile, Fatigue

• A 0.2% proof stress of 192 ± 17 MPa was found for as-built A357 samples built in the vertical orientation.

• A fatigue strength of 60 ± 5.3 MPa was obtained.

X Line R (Concept Laser)[36]Beretta et al. ()AlSi10MgLaser power 350 W, hatch distance 0.13 mm, scan speed mm/s, layer thickness 50 µm, preheating of build platform up to 150 °C.
Build orientation: Horizontal (0°), Inclined (45°), and Vertical (90°).Fatigue strength

• Moderate correlation between the surface features at the origin of the fracture and surface roughness of the printed parts was found.

• Horizontal-built specimens had highest fatigue strength compared to inclined- and vertical-built specimens.

• EIFS and fatigue life prediction models were developed and verified using experimental data. The estimated cycles to failure was found within factor of 0.5&#;2 of the experimental values.

SLM 280HL v1.0 [37]Biffi et al. ()AlSi10MgPulsed wave laser: laser power 300 W, build platform temperature 170 °C, exposure time 120 µs, point distance 130 µm, spot size 130 µm, hatch distance 140 µm, layer thickness 25 µm and build chamber environment argon.
Continuous wave laser: laser power 350 W, build platform temperature 150 °C, laser travel speed mm/s, spot size 80 µm, hatch distance 170 µm, layer thickness 50 µm and build environment argon.Compression

• The continuous wave (CW) and pulsed wave (PW) showed similar Si network, however they varied in liquid melt pool. The continuous wave yielded better strength in compression, which resulted in reduced influence of the sample build orientation on compression behaviour.

• The samples built with CW laser emission was found to have better compressive strength than those processed with PW.

• The anisotropy is better exhibited in PW than CW.

Renishaw AM 250 system
SLM Solutions SLM 500 system[38]Boschetto et al. ()AlSi10MgLaser power 370 W, scan speed mm/s, hatch spacing 190 µm, layer thickness 30 µm, laser beam diameter 100 µm, hatch rotation 67°.Roughness

• Surface roughness prediction model that incorporates the staircase effect and defects arising due to satellites particles in the feedstock powder and the balling effect was developed.

• A case study on the surface roughness of a Pelton bucket was carried out, comparing the experimental values of surface roughness of curved complex surfaces to that of the model predicted data.

EOSINT® M290 [39]Brandl et al. ()AlSi10MgLaser power 250 W, beam diameter 0.2 mm, layer thickness 50 µm, scanning speed 500 mm/s, scan spacing 0.15 mm and argon gas shielding, with and without build plate heating, build plate heating temperature 300 °C.
Build orientation: 0°, 45°, and 90°.Fatigue (using tensile samples), fracture analysis

• Post heat treatment was found to have the most considerable effect, whereas the build orientation was found to have the least considerable effect on fatigue resistance.

• Heating the build plate to 300 °C tended to neutralize the anistotropy effects due to build orientation of the samples as well as enhanced the fatigue resistance.

• The fatigue limit and the static tensile strength significantly correlate with each other.

Trumpf TrumaForm LF130 powder-bed machine [40]Buchbinder et al. ()AlSi10MgLaser power 195 W, layer thickness 30 µm, scanning speed 800 mm/s, hatch distance 150 µm, hatch rotation 67°, preheating temperatures 100°, 150°, 200°, and 250°.Distortion

• Distortions in part geometry reduced from 10.6 mm to nearly zero after preheating at 250 &#;.

• Reduction in hardness along with better resistance to crack growth was observed when the build plate was preheated.

• With preheating, lower temperature gradient results in lower thermal stresses in the printed parts.

EOSINT M 270[41]Casati et al. ()AlSi10MgLaser power 340 W, hatch distance 0.2 mm, scan rate mm/s, layer thickness 30 µm, platform temperature 160 °C.Tensile

• Ageing of parts printed on cold-platform resulted in higher hardness and tensile strength compared to hot-platform printed and aged parts.

• The standard T6 temper heat treatment resulted in higher ductility but lower mechanical strength.

EOS M290 SLM system[42]Ch et al. ()AlSi10MgLaser power 370 W, scan speed mm/s, hatch spacing 0.19 mm, layer thickness 30 µm, preheating up to 300 °C.
Build orientation: Horizontal and Vertical.Tensile, surface roughness, porosity, fracture morphology

• The samples built under both argon and nitrogen exhibited similarity in defect structure, microstructure and nearly isotropic behaviour in mechanical properties.

• In the vertical orientation under nitrogen atmosphere, samples exhibited tensile strength of 385 ± 5 MPa, whereas, at horizontal orientation under argon atmosphere, samples exhibited the lowest strength of 338 ± 2 MPa.

• The meso-structure and microstructure of the material revealed the characteristic nature of SLMed AlSi10Mg alloy which contains melt pool tracks, columnar grains and cellular structure.

EOS M280 machine[43]Chen et al. ()AlSi10MgLaser power 350 W, scan speed mm/s, layer thickness 50 µm, hatch spacing 240 µm. Tensile

• Orowan looping leads to high strength and high strain hardening capability.

• The hierarchical structure yields high yield strength of 300 MPa and UTS of 455 MPa.

SLM 250HL, SLM Solutions[44]Chou et al. ()AlSi12Laser power 0.5&#;4.5 kW, travel speed 90&#;180 mm/min, spot size 150 µm, hatch distance 0.1 mm, layer thickness 0.1 mm.Hardness, density

• Using pulsed laser for printing was demonstrated wherein Si refinement to size below 200 nm was achieved.

• The print part density was 95% and hardness was 135 HV when using pulsed laser for fabrication.

In house built Pulsed-SLM facility[45]Chou et al. ()A356 (AlSi7Mg0.3) Laser power (peak) 5 kW, square pulse, hatch distance 0.1 mm, layer thickness 100 µm, bidirectional zigzag scanning pattern, argon atmosphere.Density

• Dense parts (98 ± 0.4%) were fabricated using customized pulsed laser SLM system.

• Hunt&#;s criterion predicted primarily a columnar grain structure throughout the pulsed laser printed parts which was confirmed through electron backscatter diffraction (EBSD) observations.

In house built Pulsed-SLM facility[21]Dai and Gu ()AlSi10Mg compositeLaser power 180 W, scan speed 100, 200, 300, and 400 mm/s, laser energy per unit length (LEPUL) 450, 600, 900, and J/m.Numerical simulation, thermodynamics of the molten pool

• The oxidation played a significant role in the melt pool dynamics with thermo-capillary convection where convection took place from inward to outward flow pattern.

• The thermocapillary flow yields a driving force for the migration and rearrangement of reinforcing particles in the melt pool.

In house SLM [46]Dai et al. ()AlSi10Mg compositeLaser power 200 W, layer thickness 30 µm, scanning speed 100&#;300 mm/s, hatch spacing 60&#;100 µm.Wear

• The wear resistance was significantly influenced by the densification rate, distribution state and the powder particle size.

• Lowest wear rate of 3.4 × 10&#;4 mm3 N&#;1 m&#;1 was found when using an optimised laser volume energy density of 420 J/mm3.

In house SLM [47]de Menezes et al. ()A357Laser power 200 W, layer thickness 25 µm, hatch distance 115 µm.
Isothermal aging at 160 °C for 4 h.Tensile

• The yield strength of the horizontal-built samples was considerably greater than that of the vertical-built samples.

• The yield strength of the samples in artificially aged condition was greater than the as-built condition.

• A crack orthogonal to the building orientation results in a significant decrease in fracture toughness of the printed samples.

Renishaw AM250 SLM system[48]Delahaye et al. ()AlSi10MgLaser power 175 W, scan speed 195 mm/s, layer thickness 60 µm, preheating temperature 200 °C.Nanohardness, fracture morphology, tensile

• The fracture likely occurs in the heat-affected zone (HAZ) region due to the presence of coarse non-coherent Si precipitates.

• The intercellular network of eutectic structure is partially broken in the HAZ regions, thereby facilitating dislocation slip and plastic strain localisation.

• The cells size of the HAZ was found to match with the size of the dimples on the fracture surfaces.

MTT SLM 250[49]Deleroisse et al. ()AlSi10MgLaser power 250 W, scan speed 571 mm/s, layer thickness 60 µm, and argon atmosphere.
Heat treatment: T6 heat treatment, annealing at 525 °C for 5 h, water quench and then artificial ageing at 165 °C for 7 h.Porosity, strut properties

• Large levels of porosity and heterogenous microstructure was observed in inclined strut.

• Amount of hydrogen detected in the samples was larger than the hydrogen solubility in the liquid melt pool.

• Heat treatment suppresses microstructural heterogeneities.

-[50]Denti ()A357Laser power 950 W, scanning speed mm/s, hatch distance 0.2 mm, laser spot 400 µm, nitrogen chamber atmosphere, preheated at 200 °C and skin-core scan strategy.Shear, Tensile

• Yield strength (195 ± 17 MPa) and modulus (77.8 ± 6.8 GPa) were found to be maximum at 45° inclined samples.

• The ultimate tensile strength and shear strength of vertical-built samples were found to be the highest, 305 ± 15 MPa and 192 ± 9 MPa, respectively.

Concept Laser X Line R[51]Ding and Wang ()AlSi10MgLaser power 400 W, laser beam radius 67.5 µm, hatch space 130 µm, scan speed 300 mm/s.Modelling and simulation, density, hardness

• There is negligible effect of exposure time on heat transfer, fluid flow, and melt pool dimension.

• The simulated temperature and melt pool dimensions increase with an increase in point distance.

-[52]Dong et al. ()AlSi10MgLaser power 370 W, laser spot size 100 µm, hatch spacing 190 µm, scanning speed mm/s, layer thickness 30 µm, argon chamber atmosphere.Tensile, porosity, fractography

• The size effect has a significant influence on the geometric imperfection for SLM-processed AlSi10Mg strut.

• The porosity level of the sample decreased from 1.87% to 0.1% with the variation of build size from 1 mm to 5 mm.

• The overall strength and modulus decreased by approximately 30% with decrease in the build size.

Concept X-line R machine [53]Everitt et al. ()AlSi10MgLaser power 100 W, scan speed 250 mm/s, hatch space 50 µm, argon atmosphere.Nanohardness

• Chemical composition mapping and nano-indentation showed higher hardness in the SLM material compared to its cast counterpart.

• The printed samples exhibited a nanohardness of 9 ± 1 GPa, compared to 0.97 ± 1 GPa for the cast samples.

Realizer SLM-50[54]Fefelov et al. ()AlSi12-Fracture surface morphology, tensile

• The samples demonstrated yield and tensile strengths of about 102 MPa and 425 MPa, respectively, along with fracture strain of 12%.

EOSINT M 280 device[55]Fiegl et al. ()AlSi10MgLaser power W, layer thickness of 50 µm, volume energy 40 J/mm3, island scanning strategy and nitrogen atmosphere.Tensile

• The impact of preheating on tensile strength in x/y plane seems to be more pronounced than the impact of beam deflection.

• UTS was found to be higher without preheating, 377 ± 16 MPa, compared to samples printed with preheating strategy, 355 ± 15 MPa.

X LINE R (modified)[56]Fiocchi et al. ()AlSi10MgLaser power 300 W, spot size 130 µm, layer thickness 25 µm, hatch distance 140 µm, and argon atmosphere.Differential scanning calorimetry, hardness

• Two exothermic phenomena involving Mg2Si precipitation and Si diffusion were found.

• Isothermal transformation temperatures were identified to be 263 °C and 294 °C.

Renishaw AM250[57]Fousova et al. ()AlSi10MgLaser power 350 W, layer thickness 50 µm, scanning speed 500 mm/s, hatch spacing 170 µm, argon atmosphere and chessboard scanning strategy.Tensile

• Printed samples subjected to elevated temperatures underwent microstructural and mechanical property changes.

• At the tested temperature of 160 °C, a slight increase in tensile yield strength (by 5%) but also a strong reduction in elongation (by 60%) were observed.

SLM Solution 280HL machine[58]Gokuldoss Prashanth et al. ()AlSi12Laser power 320 W, scan speed mm/s, layer thickness 50 µm, hatch spacing 110 µm and argon atmosphere.Tensile

• The as-built samples exhibited a yield strength of 240 ± 1 MPa and UTS of 385 ± 4 MPa.

• After annealing at 300 °C, the yield strength and UTS reduced to 138 ± 3 MPa and 205 ± 5 MPa, respectively.

• The softening behaviour of the Al matrix was inversely proportional to strain hardening behaviour.

SLM 250 HL[18]Girelli et al. ()AlSi10MgLaser power 400 W, beam diameter 100 µm, argon atmosphere.
Build orientation: Horizontal and Vertical
Heat treatment: Solutionising at 540 °C for 1&#;9 h, followed by ageing at 160 °C for 4 h or 180 °C for 2 h.Impact properties, fracture morphology

• The fracture in the horizontal samples propagated along the hatch overlap regions whereas in the vertical samples the crack propagation was primarily along the inter-layer regions.

• The building orientation has a significant influence on the properties of the printed samples even after post heat treatment is applied.

• After hot isostatic pressing the samples, the porosity reduced considerably, and the fracture toughness of the specimens improved.

EOS M290 system[59]Gong et al. ()AlSi10Mg-Tensile

• The mechanical properties of AlSi10Mg parts produced by SLM are much higher than the alloy formed by conventional casting.

-[60]Hadadzadeh et al. ()AlSi10MgLaser power 370 W, beam spot size 100 µm, scanning speed mm/s, hatch spacing 190 µm, layer thickness 30 µm, argon atmosphere.
Build orientation: Horizontal and Vertical.Dynamic compression

• Columnar cellular structure was observed in the horizontal-built samples, whereas equiaxed structure was observed in the vertical-built samples.

• The dislocation density in the as-built horizontal and vertical samples was 1.14 × m&#;2 and 3.05 × m&#;2, respectively.

• These dislocation networks converted to low angle grain boundaries through dynamic recovery process to reduce the energy, thereby resulting in softening of the samples.

EOS M290 machine[61]Hadadzadeh et al. ()AlSi10MgLaser power 370 W, scanning speed mm/s, hatch spacing 190 µm, layer thickness 30 µm, stripe scanning strategy, argon atmosphere.Dynamic compression

• The samples exhibited strain hardening at strain rates lower than s&#;1, and at higher strain rates they displayed double peak flow stress deformation regime.

• Strengthening mechanisms included Hall-Petch contributed by cell walls, Orowon contributed by Si precipitates, and dislocation hardening.

• Both cell walls and Si precipitates contribute to impeding the dislocation motion and development of dislocation networks.

EOS M290[62]Han and Jiao ()AlSi10MgLaser power 200 W, hatch spacing 130 µm, layer thickness 25 µm, scanning speed 500 mm/s, chessboard bidirectional scanning strategy.
Heat treatment: Solution-treated at 550 °C for 2 h, followed by furnace cooling.
Laser surface remelting treatment: Laser power 20 W, beam diameter 32 µm, scanning speed 300 mm/s, layer thickness 0.01 mm.Tensile, Hardness, Roughness

• The surface roughness of the laser surface remelted samples was significantly reduced (0.93 µm) compared to the as-built samples (19.3 µm).

• The yield strength reduced from 200 MPa in the as-built samples to 100 MPa in the heat-treated samples.

• The laser surface remelting process improved the microhardness by 19.5% through refining the microstructure.

Renishaw AM250[63]Hatamleh et al. ()A357Heat treated at 170 °C for 3 h.
Laser shock peening applied.Finite element analysis, residual stress analysis, tensile testing

• Laser shock peening induced tensile residual stresses within certain regions of the samples.

• Tensile tests were conducted, and the results were evaluated with finite element analysis by using Johnson-Cook parameters.

-[64]Hitzler et al. ()AlSi10Mg Tensile

• Post heat-treatment resulted in homogeneous microstructure, thereby exhibiting remarkable improvement in ductility.

SLM 280HL machine[65]Hitzler et al. ()AlSi10MgLaser power 350 W, hatch spacing 0.42 mm, scan speeds 600&#;930 mm/s, base plate heating 200 °C.
Build orientation: horizontal, inclined (45°), and vertical.Fracture toughness

• The fracture toughness was found to be 40.63 KMPa.m0.5.

• The vertical-built samples were found to have poor fracture toughness.

SLM 280HL machine[66]Hitzler et al. ()AlSi10MgLaser power 350 W, hatch spacing 0.42 mm, scan speeds 600&#;930 mm/s, base plate heating 200 °C, nitrogen atmosphere.Tensile, surface hardness

• The elastic modulus, tensile strength, and elongation were found to be sensitive to the part print orientation.

• For the non-heat-treated condition, the Young&#;s modulus varied from 62.5 to 72.9 GPa, the Poisson&#;s ratio ranged from 0.29 to 0.36, UTS from 314 MPa to 399 MPa, and elongation from 3.2% to 6.5%.

• The heat-treated samples exhibited dissimilar responses to an additional aging procedure and were dependent on the build height.

SLM 280HL machine[67]Hitzler et al. ()AlSi10MgLaser power 400 W, layer thickness 50 µm, nitrogen atmosphere.Tensile, compression

• Young&#;s modulus of the printed samples exceeded the nominal value of &#;70 GPa.

• Vertical-built samples showed the least elastic modulus.

• A maximum compressive strength value of 530 MPa was attained.

SLM 280HL machine[68]Hu et al. ()AlSi10MgLaser energy input 700&#; J/m, layer thickness 50 µm, argon atmosphere.CFD model, thermal gradient

• The results show that the temperature and molten pool depth gradually increases with new layers and energy input.

• The cooling rate increases progressively while the solidification morphology parameter decreases with the increase of energy input.

• The increase in energy input lead to non-linear increase in melt pool depth and remelting depth.

-[69]Iturrioz et al. ()AlSi10MgLaser power 400 W, protective atmosphere.
Heat treatment: Stress-relieving (heating rate of 10 °C/min until 300 °C for 2 h), Solution-treated at 450 °C and 550 °C for 2 h, followed by water quenching, and T6 heat treatment.Tensile, hardness, density

• The as-built samples achieved a relative density of 99.9%. After heat treatments, Si forms polygonal precipitates whose size increases as the temperature increases. This results in a decrease in tensile strength and hardness with heating up to 450 °C.

• T6 heat treatment (550 °C for 2 h followed by ageing at 180 °C for 12 h) was found to be best performing, which yielded the tensile strength of 307 ± 8 MPa, hardness 101 ± 4 HV and ductility 9 ± 3%.

SLM 280HL machine[70]Jawade et al. ()AlSi10MgLaser power 250 W, beam diameter 0.2 mm, layer thickness 50 µm, scanning speed 500 mm/s. Tensile

• The horizontal build orientation yielded better tensile strength when compared to samples built in the vertical orientation. Furthermore, microstructure revealed anisotropy and its dependency on build orientation.

• The UTS was found to be maximum on horizontal orientation (401.89 MPa), yield strength (301.26 MPa) and elongation of 4.3%, which is superior than the counterpart at vertical orientation.

Renishaw AM 250[71]Jiang et al. ()AlSi10Mg compositeLaser power 370 W, scan speed ranging from 900&#; mm/s, scan spacing 105 µm, layer thickness 30 µm, zigzag scan strategy. Tensile, hardness, density

• The hardness and tensile strength improved by approx. 10% and 20%, respectively, with the addition of 1 wt% CNTs.

Concept Laser M2 Cusing SLM system [72]Jing et al. ()AlSi10MgHatch spacing 190 µm, layer thickness 30 µm, volume energy density 26&#;54 Jmm&#;3, laser power 310&#;390 W, scanning speed &#; mm/s, chamber pressure 0.45 mbar.
Build orientation: Horizontal and Vertical.Porosity, microhardness, tensile testing and fracture morphology

• Microstructure of the samples printed using optimised process parameters consisted of extremely fine Al-Si eutectic dispersed within primary α-Al dendrites.

• Hardness in the transverse direction was higher than that along the longitudinal direction.

• The engineering stress-strain curve at different orientations also shows anisotropy in the strength and ductility, which is possibly due to the orientation between the tensile stress and crystal growth direction.

EOS 83 M290 SLM[73]Kang et al. ()AlSi12Laser power 400 W, scanning speed mm/s, layer thickness 50 µm and hatch distance 45 µm.Tensile

• Ultrafine microstructure consisting of cellular α-Al and nano-sized Si particles was found due to the high cooling rate of the SLM process

• As the laser scanning speed increases, both tensile strength and ductility of SLM processed samples decrease.

• Higher energy density was required to fabricate dense samples from in-situ SLM fabrication using elemental Al and Si powders, compared to pre-alloyed Al-12Si powders.

Realizer SLM 250 machine[74]Kempen et al. ()AlSi10Mg200 W fiber laser, laser beam diameter 150 µm, scan speed mm/s, scan spacing 105 µm.
Build orientation: Horizontal and Vertical.Tensile

• Mechanical properties of printed parts comparable or even exceeding those of conventionally cast AlSi10Mg.

• Maximum UTS observed for vertical samples 396 ± 8 MPa, but the elongation was better for the horizontal orientation 5.55 ± 0.4%.

Modified Concept Laser M1 SLM Machine[4]Kempen et al. ()AlSi10MgLaser power 300 W, laser spot size 80 µm, scan speed mm/s.
Build orientation: XY and Z.Surface roughness, Metrology

• Samples printed in the Z-orientation has to be compensated for the width of the melt pool.

• Samples printed in the XY-orientation showed dross formation.

In-house built SLM machine[75]Kempen et al. ()AlSi10Mg200 W fiber laser, laser beam diameter 150 µm, scan speed mm/s, scan spacing 105 µm and layer thickness 30 µm.
Build orientation: Horizontal and Vertical.Tensile, Hardness

• Mechanical properties of printed parts comparable or even exceeding those of high pressure die cast AlSi10Mg.

• Hardness found to be 152 ± 5 HV after ageing at 175 °C for 6 h.

Modified Concept Laser M1 SLM Machine[76]Kempen et al. ()AlSi10Mg170 to 200 W fiber laser, laser beam diameter 150 µm, scan speed 200&#; mm/s, scan spacing 105 µm and layer thickness 30 µm.
Build orientation: Horizontal and Vertical.Density, Roughness

• Narrow process window to obtain optimal density and surface quality for printed parts.

• Higher scan speed of mm/s was used for high density/productivity demands, whereas lower scan speeds of &#; mm/s were used for parts with a high demand in top surface quality.

Modified Concept Laser M1 SLM Machine[77]Kim et al. ()AlSi10MgLaser power 200 W, scanning speed mm/s, bidirectional scanning vector.Tensile

• Significant stress partitioning exists between the Si (680 MPa) and Al (260 MPa) constituents.

• The fracture analysis reveals large voids and cracks in the microstructure, particularly in the soft Al matrix under loading.

Concept Laser M2 machine[78]Kimura and Nakamoto ()A356Laser power 200&#;370 W, scan speed 400&#; mm/s, scan spacing 0.08&#;0.18 mm, layer thickness of 30 µm.Tensile, Density

• Relative density of 99.8% could be obtained by optimizing the laser irradiation conditions.

• Tensile strength of 400 MPa, yield strength of 200 MPa, and elongation of 12&#;17% was obtained for optimally printed samples.

• After annealing the UTS reduced to 250 MPa and yield strength to 125 MPa, however, elongation increased to 30%.

EOSINT M280 SLM [20]Krishnan et al. ()AlSi10Mg200 W Yb fiber laser, layer thickness 20&#;40 µm, beam diameter 0.1 mm, laser power 180&#;195 W, scanning speed 700&#;900 mm/s, hatch distance 0.1&#;0.25 mm, nitrogen atmosphere.Hardness, Density

• Hatch distance is the most influential process parameter affecting the print part density.

• There is a close correlation between the geometry of scan tracks and macroscopic properties of the printed parts.

• The optimal energy density was found to be 1.2&#;1.8 J/mm2.

-[79]Li et al. ()AlSi10MgLaser power 350 W, beam diameter 80 µm, scan speed mm/s, layer thickness 50 µm, scan spacing 170 µm, argon chamber atmosphere, substrate plate pre-heated to 100 °C.
Heat treatment: T6 treatment, solution treated at 450 °C, 500 °C, and 550 °C for 2 h, water quenched, and aged at 180 °C for 12 h.Tensile, hardness

• The solubility of Si in the Al matrix of the as-built samples was found to be about 8.89 at%, which significantly decreased after solution heat treatment, and further decreased with ageing treatment.

• The tensile strength decreased from 434.25 ± 10.7 MPa for the as-built specimens to 168.11 ± 2.4 MPa for the specimens that were solution heat-treated only. However, the fracture strain increased from 5.3 ± 0.22% to 23.7 ± 0.84%.

SLM250 HL[80]Li et al. ()AlSi10MgBuild orientation: Horizontal (Y-direction) and Vertical (Z-direction), tensile testing carried out at &#;71 °C. Tensile

• The tensile strength and elongation of the horizontally-built samples are 340 MPa and 11.2%, respectively, compared to 350 MPa and 13.4%, respectively, for the vertically-built samples.

• The microstructure revealed fish-scale morphology along the Y-build direction and oval shaped structure in the Z-build direction.

-[81]Li et al. ()AlSi12Laser power 200 W, scanning speed 500 mm/s, layer thickness 50 µm, scan spacing 150 µm, substrate heated to 200 °C, argon atmosphere.
Heat treatment: Solution treated at 500 °C for 4 h and water quenched.Tensile, residual stresses, FEM

• Spherical Si particles with size less than 100 nm formed at the Al grain boundaries. However, the coarse and fine Si precipitates were found to be homogeneously distributed in the Al matrix.

• The ultrafine eutectic microstructure yields significantly better tensile properties and an extremely high ductility of approx. 25% after solution heat treatment.

ReaLizer SLM-100 machine[82]Li et al. ()AlSi10MgLaser power 200 W, hatch spacing 80 µm, laser spot diameter 80 µm, layer thickness 25 µm, exposure time 100&#;180 µs, point distance 60&#;100 µm.Modelling and simulation

• A 3D FE model was developed to simulate the thermal behaviour and melt pool dimensions of the printed parts.

• The cooling rate of the melt pool reduced from 7.93 × 106 °C/s to 3.61 × 106 °C/s as the laser exposure time is increased from 100 µs to 180 µs. Alternatively, with an increase in point distance from 60 µm to 100 µm, the cooling rate increased from 3.25 × 106 °C/s to 7.48 × 106 °C/s.

• The melt pool size (width and depth) increased as the laser exposure time is increased, and vice-versa when the point distance is increased.

Renishaw AM 400 SLM system (Renishaw PLC)[83]Li and Gu ()AlSi10MgLaser power of 150&#;300 W, laser spot diameter 70 µm, scanning speed 100&#;400 mm/s, layer thickness 50 µm, hatch spacing 50 µm, argon atmosphere.Modelling and simulation

• SLM experimental results validated the obtained thermal behavior in simulation.

• The cooling rate increased from 2.13 × 106 °C/s to 2.97 × 106 °C/s when the laser power was increased from 150 W to 300 W, and from 1.25 × 106 °C/s to 6.17 × 106 °C/s when the scan speed increased from 100 mm/s to 400 mm/s.

• A sound metallurgical bonding between the neighboring layers was obtained at the optimized combination of process parameters, including laser power of 250 W and scan speed of 200 mm/s.

YLR-500-SM[84]Liu et al. ()AlSi10MgLaser power 200 WTensile, hardness, density, roughness

• An 80% decrease in surface roughness was observed when the printed parts were sand blasted.

• The tensile properties of the as-built samples tested at both room temperature and high temperature (200 °C) are significantly better than the conventionally heat-treated cast parts.

M2 Cusing from Concept Laser, Germany[85]Liu et al. ()AlSi10MgLaser power 500 W, scan speed mm/s, layer thickness 30 µm, zigzag scan strategy, scanning angle alternated by 90° for subsequent layers.Hardness, wear resistance, modelling and simulation

• The cooling rate for the layers printed at the top region of the sample was determined to be about 1.44 × 106 K/s, which is significantly higher than that experienced by the bottom layers (&#; 1 × 103 K/s).

• The top surface area has a lower degree of crystallinity of Al matrix than that of core area.

• The surfaces of the printed samples exhibited higher hardness and wear resistance compared to the core regions.

BLT-S300 SLM machine[86]Liu et al. ()AlSi10MgLaser power 160&#;200 W, spot size 100 µm, scanning speed 200&#; mm/s, argon atmosphere.Modelling and simulation

• The cooling rate, temperature gradient and the solidification rate increase with an increase in laser power and decrease with an increase in scanning speed.

• Along Z direction, the cooling rates and the temperature gradient are lower compared to Y direction.

IPG YLR-200[87]Louvis et al. ()AA Laser power 50&#;100 W, laser spot size 80 µm, hatch spacing 0.05&#;0.3 mm, scan speed range 75&#; mm/s, layer thickness 50 µm, argon atmosphere, point distance 65&#;85 µmDensity

• The formation of oxides can be avoided by using high laser powers while printing.

• The maximum relative density was obtained at high laser power of 100 W (89.5%).

MCP Realizer 100 SLM machine[8]Maamoun et al. ()AlSi10Mg & AA For AA : Laser power 300&#;370 W), scanning speed 800&#; mm/s, hatch spacing 0.1&#;0.19 mm, energy density 40.5&#;123.3 J/mm3.
For AlSi10Mg: Laser power 200&#;370 W), scanning speed &#; mm/s, hatch spacing 0.15&#;0.25 mm, energy density 27&#;65 J/mm3. Tensile, hardness

• The microstructure of AA parts did not show the same fibrous Si network that formed inside the AlSi10Mg microstructure due to lower Si content.

• The size of the melt pool increases with an increase in energy density. An energy density range of 50 to 60 J/mm3 was found to be optimum to significantly minimize the formation of keyhole defects and porosities.

• Maximum tensile strength of both the AlSi10Mg and AA printed samples was 396.5 MPa.

-[88]Maconachie et al. ()AlSi10MgLaser power 350 W, scanning speed mm/s, layer thickness 30 µm, hatch spacing 130 µm and beam diameter 90 µm.
Build Orientation: 0°, 45° and 90°. Tensile, dynamic behaviour in tension (SHTB), fracture

• The tensile strength is not significantly affected by the build orientation of the printed samples.

• Samples built perpendicular to the build direction failed at greater strain than those built parallel to the build direction.

• The anisotropic properties of the samples were insensitive to the strain rate applied during mechanical testing.

SLM500[89]Majeed et al. ()AlSi10MgLaser power 320 W, hatch spacing 0.08 mm, layer thickness 30 µm, scanning speed 900 mm/s, checkerboard scanning strategy, argon atmosphere.
Heat Treatment: T4 treatment involving solution heat treated at 530 or 540 °C for 2 h and water quenched. T6 treatment involving solution treated at 530 °C for 2 h, water quenched and artificially aged at 155 °C for 12 h.Density, tensile, fracture

• As the wall thickness increased from 0.5 mm to 1.5 mm, an increase in porosity was observed.

• Ageing heat treatment resulted in better density of the thin wall samples.

• The size of the pores increased till the wall thickness of 1.5 mm and then decreased with further increase in wall thickness.

280 HL SLM[90]Maskery et al. ()AlSi10MgLaser power 200 W, layer thickness 25 µm, hatch spacing 130 µm, scanning speed 571 mm/s, point distance 80 µm, exposure time 140 µs, build platform temperature 180 °C, hatch rotation 67°.
Heat treatment: Solution treated at 520 °C for 1 h, water quenched, and aged at 160 °C for 6 h.Tensile, fatigue

• The elongation at break for the heat-treated material was nearly three times greater than that observed for the as-built material, and the fatigue strength at 106 cycles was around 1.6 times as high.

• The UTS was reduced from 330 ± 10 MPa to 292 ± 4 MPa and the ductility enhanced from (1.4 ± 0.3)% to (3.9 ± 0.5)%.

Renishaw AM250 SLM machine[91]Mfusi et al. ()AlSi10MgLaser power 150 W, scanning speed mm/s, hatch spacing 50 µm, and layer thickness 50 µm.
Build Orientation: XY, 45°, and Z orientations.
Heat treatment: Stress relief treatment at 300 °C for 2 h followed by furnace cooling.Tensile, fatigue crack growth, fracture toughness, density, hardness, porosity

• Anisotropy due to different build orientations was found even after post stress relief heat treatment.

  Mechanical Properties of SLM-Printed Aluminium Alloys

  Aboulkhair et al. ()AlSi10MgLaser power 200 W, layer thickness 25 µm, scan speed 550 mm/s, hatch spacing 80 µm, and scan strategy chess board.
  Heat treatment: Solution treated at 520 °C for 1 h, water quenched to room temperature and then
  aged for 6 h at 160 °C.Fatigue

  • At lower stress levels, machining the samples improved the fatigue performance, but did not have any influence at higher stress levels.

  • Heat treating the samples significantly improved the fatigue life, and it was found that at 94 MPa stress loading, the heat-treated samples outperformed their cast counterparts in terms of fatigue life.

  • The samples that were heat-treated and machined showed the best fatigue performance.

  Renishaw AM250[27]Aboulkhair et al. ()AlSi10MgLaser power 200 W, scan speed 550 mm/s, hatch spacing 130 µm, layer thickness 25 µm, and checkerboard scan strategy.
  Heat treatment: T6Tensile strength, compressive yield strength, nano-hardness

  • The printed parts had tensile strength better than the diecast parts.

  • After heat treatment, the hardness and the tensile strength of the printed parts reduced by about 20% and 12%, respectively, whereas the ductility increased by a factor of 2.8.

  • The compressive yield strength of the heat-treated parts was 169 ± 6 MPa which was approximately half the strength of the as-built parts.

  Renishaw AM250[11]Aboulkhair et al. ()AlSi10MgLaser power 200 W, point distance 80 µm, exposure time 140 µs, hatch spacing 130 µm, layer thickness 25 µm and checkerboard scan strategy.Tensile and compressive strength, nano-hardness

  • Uniform nano-hardness of 1.82 ± 0.01 GPa was observed in the SLMed samples due to the homogeneous distribution of Si particles segregating at α-Al grain boundaries.

  • Microhardness along the plane parallel to the build plane was found to be higher (109.7 ± 0.9 HV) than the plane perpendicular to the build plane (99.07 ± 2 HV).

  Renishaw AM250[12]Alghamdi and Haghshenas ()AlSi10MgTwo 400 W lasers at CalRAM Inc. were used, with default SLM 280 parameter set.
  Heat Treatment: T6, solutionising at 520 °C for 1 h, followed by water quench, then artificial ageing at 170 °C for 4 h.Nano-hardness

  • The nano-hardness of the heat-treated samples (1.56 ± 0.11 GPa) was reduced by 42% compared to the strength of the as-built samples (2.71 ± 0.12 GPa).

  • Heat treatment of the samples resulted in the change in microstructure from cellular grains to fragmented/spheroidised eutectic silicon particles.

  • The effect of the indentation size was observed in both as-built and heat-treated samples. With the decrease in the depth of indent, the hardness increased.

  400 W laser at CalRAM Inc.
  SLM 280[28]Amani et al. ()AlSi10MgLaser power 250 W, scanning speed 571 mm/s, layer thickness 60 µm, and argon gas atmosphere.Compression behaviour

  • Deformation behaviour of two face-centred cubic lattice structures with thin and thick struts was studied using both in-situ and ex-situ X-ray computed tomography technique.

  • A finite element model was developed using Gurson-Tvergaard-Needleman (GTN) porous plasticity model.

  • Simulations showed a fairly good agreement with the model&#;s prediction of fracture location.

  SLM 250[29]Anwar & Pham ()AlSi10MgLaser power 350 W, layer thickness 100 µm, laser speed 900 mm/s, and hatch spacing of 0.12 mm.Tensile strength

  • The quality of the as-built samples depended upon the velocity of the gas flow in the built chamber, the direction of laser scan with respect to the gas flow direction, and position of the part with respect to the chamber outlet location.

  • Higher ultimate tensile strength (UTS) values for parts printed with laser scan direction against the gas flow, with higher gas velocity, and closer to the outlet was observed.

  • When the laser scanning was in the direction of gas flow, a reduced accumulation of spatter powder particles was observed near the outlet.

  SLM Solutions 280 HL[30]Asgari et al. ()AlSi10MgLaser power 370 W, scanning speed mm/s, hatch distance 190 µm, powder layer thickness 30 µm, build platform pre-heating temperature 200 °C.
  Build orientation: Vertical and Horizontal.Dynamic compression, Split Hopkinson pressure bar testing

  • Increasing the strain rate from 150 s&#;1 to s&#;1 resulted in higher yield, peak flow stress, and ductility.

  • The texture evolution could be attributed to vertical build orientation than horizontal build orientation due to uniform and dense microstructure, while the texture is not affected by the deformation at high strain rates.

  EOS M290 machine [31]Aversa et al. ()A357Laser power 195 W, scan speed mm/s, layer thickness 30 µm, hatching distance 0.1 mm and stripe scanning strategy.Tensile

  • Effect of build plate heating on the tensile properties was evaluated and build plate heating temperatures of 140 °C and 170 °C were reported to yield highest tensile strength of 408 ± 5 MPa and a yield strength of 284 ± 3 MPa.

  • The platform heating induces artificial ageing within the print-parts during processing.

  • Low platform heating temperatures result in under-ageing whereas high platform heating temperatures result in over-ageing of the printed samples.

  EOS M270 Dual Mode system[32]Awd et al. ()AlSi10MgProcess parameters not disclosed.
  Build orientation: 0°, 45° and 90° with respect to the build plate.Tensile

  • The pore density of 90° built samples were seven times higher than the 0° built samples.

  • The 0° built samples displayed 8% higher tensile strength than the samples built at 90° orientation.

  • Samples fabricated along the 45° orientation had a significantly reduced fracture strain.

  M2 Cusing system[33]Baitimerov et al. ()AlSi12Laser power 200 W, layer thickness 50 µm, stripe hatch scanning strategy, powder dried at 100 °C for 1 h and the oxygen inside the build chamber was maintained below 500 ppm.Density

  • Using the optimised process parameters, a relative density > 99% was achieved.

  • The AlSi12 powder with good flowability and apparent density leads to good processability in SLM, while highly fine and spherically shaped powder particles result in poor processability.

  • The particles with nearly spherical shaped morphology exhibited very poor flowability, leading to high porosity levels.

  Sinterstation® Pro DM125 SLM System[34]Bao et al. ()AlSi10MgLaser power ranging 360 W&#;400 W, layer thickness 0.05 mm, laser scanning speed mm/s&#; mm/s, scan spacing 0.13&#;0.16 mm.Fatigue

  • The cyclic plasticity occurs when the longitudinal strain exceeds 0.9.

  • The failure of the printed parts was attributed to the presence of large density of secondary micro-voids.

  • The elongation of original defects along the loading direction is 10 times faster than that along the lateral side.

  BLT S310[35]Bassoli et al. ()A357Laser power 950 W, scan speed mm/s, spot size 400 µm, hatch distance 0.2 mm, layer thickness 50 µm, nitrogen gas chamber atmosphere, preheating temperature 200 °C and skin core scan strategy.Tensile, Fatigue

  • A 0.2% proof stress of 192 ± 17 MPa was found for as-built A357 samples built in the vertical orientation.

  • A fatigue strength of 60 ± 5.3 MPa was obtained.

  X Line R (Concept Laser)[36]Beretta et al. ()AlSi10MgLaser power 350 W, hatch distance 0.13 mm, scan speed mm/s, layer thickness 50 µm, preheating of build platform up to 150 °C.
  Build orientation: Horizontal (0°), Inclined (45°), and Vertical (90°).Fatigue strength

  • Moderate correlation between the surface features at the origin of the fracture and surface roughness of the printed parts was found.

  • Horizontal-built specimens had highest fatigue strength compared to inclined- and vertical-built specimens.

  • EIFS and fatigue life prediction models were developed and verified using experimental data. The estimated cycles to failure was found within factor of 0.5&#;2 of the experimental values.

  SLM 280HL v1.0 [37]Biffi et al. ()AlSi10MgPulsed wave laser: laser power 300 W, build platform temperature 170 °C, exposure time 120 µs, point distance 130 µm, spot size 130 µm, hatch distance 140 µm, layer thickness 25 µm and build chamber environment argon.
  Continuous wave laser: laser power 350 W, build platform temperature 150 °C, laser travel speed mm/s, spot size 80 µm, hatch distance 170 µm, layer thickness 50 µm and build environment argon.Compression

  • The continuous wave (CW) and pulsed wave (PW) showed similar Si network, however they varied in liquid melt pool. The continuous wave yielded better strength in compression, which resulted in reduced influence of the sample build orientation on compression behaviour.

  • The samples built with CW laser emission was found to have better compressive strength than those processed with PW.

  • The anisotropy is better exhibited in PW than CW.

  Renishaw AM 250 system
  SLM Solutions SLM 500 system[38]Boschetto et al. ()AlSi10MgLaser power 370 W, scan speed mm/s, hatch spacing 190 µm, layer thickness 30 µm, laser beam diameter 100 µm, hatch rotation 67°.Roughness

  • Surface roughness prediction model that incorporates the staircase effect and defects arising due to satellites particles in the feedstock powder and the balling effect was developed.

  • A case study on the surface roughness of a Pelton bucket was carried out, comparing the experimental values of surface roughness of curved complex surfaces to that of the model predicted data.

  EOSINT® M290 [39]Brandl et al. ()AlSi10MgLaser power 250 W, beam diameter 0.2 mm, layer thickness 50 µm, scanning speed 500 mm/s, scan spacing 0.15 mm and argon gas shielding, with and without build plate heating, build plate heating temperature 300 °C.
  Build orientation: 0°, 45°, and 90°.Fatigue (using tensile samples), fracture analysis

  • Post heat treatment was found to have the most considerable effect, whereas the build orientation was found to have the least considerable effect on fatigue resistance.

  • Heating the build plate to 300 °C tended to neutralize the anistotropy effects due to build orientation of the samples as well as enhanced the fatigue resistance.

  • The fatigue limit and the static tensile strength significantly correlate with each other.

  Trumpf TrumaForm LF130 powder-bed machine [40]Buchbinder et al. ()AlSi10MgLaser power 195 W, layer thickness 30 µm, scanning speed 800 mm/s, hatch distance 150 µm, hatch rotation 67°, preheating temperatures 100°, 150°, 200°, and 250°.Distortion

  • Distortions in part geometry reduced from 10.6 mm to nearly zero after preheating at 250 &#;.

  • Reduction in hardness along with better resistance to crack growth was observed when the build plate was preheated.

  • With preheating, lower temperature gradient results in lower thermal stresses in the printed parts.

  EOSINT M 270[41]Casati et al. ()AlSi10MgLaser power 340 W, hatch distance 0.2 mm, scan rate mm/s, layer thickness 30 µm, platform temperature 160 °C.Tensile

  • Ageing of parts printed on cold-platform resulted in higher hardness and tensile strength compared to hot-platform printed and aged parts.

  • The standard T6 temper heat treatment resulted in higher ductility but lower mechanical strength.

  EOS M290 SLM system[42]Ch et al. ()AlSi10MgLaser power 370 W, scan speed mm/s, hatch spacing 0.19 mm, layer thickness 30 µm, preheating up to 300 °C.
  Build orientation: Horizontal and Vertical.Tensile, surface roughness, porosity, fracture morphology

  • The samples built under both argon and nitrogen exhibited similarity in defect structure, microstructure and nearly isotropic behaviour in mechanical properties.

  • In the vertical orientation under nitrogen atmosphere, samples exhibited tensile strength of 385 ± 5 MPa, whereas, at horizontal orientation under argon atmosphere, samples exhibited the lowest strength of 338 ± 2 MPa.

  • The meso-structure and microstructure of the material revealed the characteristic nature of SLMed AlSi10Mg alloy which contains melt pool tracks, columnar grains and cellular structure.

  EOS M280 machine[43]Chen et al. ()AlSi10MgLaser power 350 W, scan speed mm/s, layer thickness 50 µm, hatch spacing 240 µm. Tensile

  • Orowan looping leads to high strength and high strain hardening capability.

  • The hierarchical structure yields high yield strength of 300 MPa and UTS of 455 MPa.

  SLM 250HL, SLM Solutions[44]Chou et al. ()AlSi12Laser power 0.5&#;4.5 kW, travel speed 90&#;180 mm/min, spot size 150 µm, hatch distance 0.1 mm, layer thickness 0.1 mm.Hardness, density

  • Using pulsed laser for printing was demonstrated wherein Si refinement to size below 200 nm was achieved.

  • The print part density was 95% and hardness was 135 HV when using pulsed laser for fabrication.

  In house built Pulsed-SLM facility[45]Chou et al. ()A356 (AlSi7Mg0.3) Laser power (peak) 5 kW, square pulse, hatch distance 0.1 mm, layer thickness 100 µm, bidirectional zigzag scanning pattern, argon atmosphere.Density

  • Dense parts (98 ± 0.4%) were fabricated using customized pulsed laser SLM system.

  • Hunt&#;s criterion predicted primarily a columnar grain structure throughout the pulsed laser printed parts which was confirmed through electron backscatter diffraction (EBSD) observations.

  In house built Pulsed-SLM facility[21]Dai and Gu ()AlSi10Mg compositeLaser power 180 W, scan speed 100, 200, 300, and 400 mm/s, laser energy per unit length (LEPUL) 450, 600, 900, and J/m.Numerical simulation, thermodynamics of the molten pool

  • The oxidation played a significant role in the melt pool dynamics with thermo-capillary convection where convection took place from inward to outward flow pattern.

  • The thermocapillary flow yields a driving force for the migration and rearrangement of reinforcing particles in the melt pool.

  In house SLM [46]Dai et al. ()AlSi10Mg compositeLaser power 200 W, layer thickness 30 µm, scanning speed 100&#;300 mm/s, hatch spacing 60&#;100 µm.Wear

  • The wear resistance was significantly influenced by the densification rate, distribution state and the powder particle size.

  • Lowest wear rate of 3.4 × 10&#;4 mm3 N&#;1 m&#;1 was found when using an optimised laser volume energy density of 420 J/mm3.

  In house SLM [47]de Menezes et al. ()A357Laser power 200 W, layer thickness 25 µm, hatch distance 115 µm.
  Isothermal aging at 160 °C for 4 h.Tensile

  • The yield strength of the horizontal-built samples was considerably greater than that of the vertical-built samples.

  • The yield strength of the samples in artificially aged condition was greater than the as-built condition.

  • A crack orthogonal to the building orientation results in a significant decrease in fracture toughness of the printed samples.

  Renishaw AM250 SLM system[48]Delahaye et al. ()AlSi10MgLaser power 175 W, scan speed 195 mm/s, layer thickness 60 µm, preheating temperature 200 °C.Nanohardness, fracture morphology, tensile

  • The fracture likely occurs in the heat-affected zone (HAZ) region due to the presence of coarse non-coherent Si precipitates.

  • The intercellular network of eutectic structure is partially broken in the HAZ regions, thereby facilitating dislocation slip and plastic strain localisation.

  • The cells size of the HAZ was found to match with the size of the dimples on the fracture surfaces.

  MTT SLM 250[49]Deleroisse et al. ()AlSi10MgLaser power 250 W, scan speed 571 mm/s, layer thickness 60 µm, and argon atmosphere.
  Heat treatment: T6 heat treatment, annealing at 525 °C for 5 h, water quench and then artificial ageing at 165 °C for 7 h.Porosity, strut properties

  • Large levels of porosity and heterogenous microstructure was observed in inclined strut.

  • Amount of hydrogen detected in the samples was larger than the hydrogen solubility in the liquid melt pool.

  • Heat treatment suppresses microstructural heterogeneities.

  -[50]Denti ()A357Laser power 950 W, scanning speed mm/s, hatch distance 0.2 mm, laser spot 400 µm, nitrogen chamber atmosphere, preheated at 200 °C and skin-core scan strategy.Shear, Tensile

  • Yield strength (195 ± 17 MPa) and modulus (77.8 ± 6.8 GPa) were found to be maximum at 45° inclined samples.

  • The ultimate tensile strength and shear strength of vertical-built samples were found to be the highest, 305 ± 15 MPa and 192 ± 9 MPa, respectively.

  Concept Laser X Line R[51]Ding and Wang ()AlSi10MgLaser power 400 W, laser beam radius 67.5 µm, hatch space 130 µm, scan speed 300 mm/s.Modelling and simulation, density, hardness

  • There is negligible effect of exposure time on heat transfer, fluid flow, and melt pool dimension.

  • The simulated temperature and melt pool dimensions increase with an increase in point distance.

  -[52]Dong et al. ()AlSi10MgLaser power 370 W, laser spot size 100 µm, hatch spacing 190 µm, scanning speed mm/s, layer thickness 30 µm, argon chamber atmosphere.Tensile, porosity, fractography

  • The size effect has a significant influence on the geometric imperfection for SLM-processed AlSi10Mg strut.

  • The porosity level of the sample decreased from 1.87% to 0.1% with the variation of build size from 1 mm to 5 mm.

  • The overall strength and modulus decreased by approximately 30% with decrease in the build size.

  Concept X-line R machine [53]Everitt et al. ()AlSi10MgLaser power 100 W, scan speed 250 mm/s, hatch space 50 µm, argon atmosphere.Nanohardness

  • Chemical composition mapping and nano-indentation showed higher hardness in the SLM material compared to its cast counterpart.

  • The printed samples exhibited a nanohardness of 9 ± 1 GPa, compared to 0.97 ± 1 GPa for the cast samples.

  Realizer SLM-50[54]Fefelov et al. ()AlSi12-Fracture surface morphology, tensile

  • The samples demonstrated yield and tensile strengths of about 102 MPa and 425 MPa, respectively, along with fracture strain of 12%.

  EOSINT M 280 device[55]Fiegl et al. ()AlSi10MgLaser power W, layer thickness of 50 µm, volume energy 40 J/mm3, island scanning strategy and nitrogen atmosphere.Tensile

  • The impact of preheating on tensile strength in x/y plane seems to be more pronounced than the impact of beam deflection.

  • UTS was found to be higher without preheating, 377 ± 16 MPa, compared to samples printed with preheating strategy, 355 ± 15 MPa.

  X LINE R (modified)[56]Fiocchi et al. ()AlSi10MgLaser power 300 W, spot size 130 µm, layer thickness 25 µm, hatch distance 140 µm, and argon atmosphere.Differential scanning calorimetry, hardness

  • Two exothermic phenomena involving Mg2Si precipitation and Si diffusion were found.

  • Isothermal transformation temperatures were identified to be 263 °C and 294 °C.

  Renishaw AM250[57]Fousova et al. ()AlSi10MgLaser power 350 W, layer thickness 50 µm, scanning speed 500 mm/s, hatch spacing 170 µm, argon atmosphere and chessboard scanning strategy.Tensile

  • Printed samples subjected to elevated temperatures underwent microstructural and mechanical property changes.

  • At the tested temperature of 160 °C, a slight increase in tensile yield strength (by 5%) but also a strong reduction in elongation (by 60%) were observed.

  SLM Solution 280HL machine[58]Gokuldoss Prashanth et al. ()AlSi12Laser power 320 W, scan speed mm/s, layer thickness 50 µm, hatch spacing 110 µm and argon atmosphere.Tensile

  • The as-built samples exhibited a yield strength of 240 ± 1 MPa and UTS of 385 ± 4 MPa.

  • After annealing at 300 °C, the yield strength and UTS reduced to 138 ± 3 MPa and 205 ± 5 MPa, respectively.

  • The softening behaviour of the Al matrix was inversely proportional to strain hardening behaviour.

  SLM 250 HL[18]Girelli et al. ()AlSi10MgLaser power 400 W, beam diameter 100 µm, argon atmosphere.
  Build orientation: Horizontal and Vertical
  Heat treatment: Solutionising at 540 °C for 1&#;9 h, followed by ageing at 160 °C for 4 h or 180 °C for 2 h.Impact properties, fracture morphology

  • The fracture in the horizontal samples propagated along the hatch overlap regions whereas in the vertical samples the crack propagation was primarily along the inter-layer regions.

  • The building orientation has a significant influence on the properties of the printed samples even after post heat treatment is applied.

  • After hot isostatic pressing the samples, the porosity reduced considerably, and the fracture toughness of the specimens improved.

  EOS M290 system[59]Gong et al. ()AlSi10Mg-Tensile

  • The mechanical properties of AlSi10Mg parts produced by SLM are much higher than the alloy formed by conventional casting.

  -[60]Hadadzadeh et al. ()AlSi10MgLaser power 370 W, beam spot size 100 µm, scanning speed mm/s, hatch spacing 190 µm, layer thickness 30 µm, argon atmosphere.
  Build orientation: Horizontal and Vertical.Dynamic compression

  • Columnar cellular structure was observed in the horizontal-built samples, whereas equiaxed structure was observed in the vertical-built samples.

  • The dislocation density in the as-built horizontal and vertical samples was 1.14 × m&#;2 and 3.05 × m&#;2, respectively.

  • These dislocation networks converted to low angle grain boundaries through dynamic recovery process to reduce the energy, thereby resulting in softening of the samples.

  EOS M290 machine[61]Hadadzadeh et al. ()AlSi10MgLaser power 370 W, scanning speed mm/s, hatch spacing 190 µm, layer thickness 30 µm, stripe scanning strategy, argon atmosphere.Dynamic compression

  • The samples exhibited strain hardening at strain rates lower than s&#;1, and at higher strain rates they displayed double peak flow stress deformation regime.

  • Strengthening mechanisms included Hall-Petch contributed by cell walls, Orowon contributed by Si precipitates, and dislocation hardening.

  • Both cell walls and Si precipitates contribute to impeding the dislocation motion and development of dislocation networks.

  EOS M290[62]Han and Jiao ()AlSi10MgLaser power 200 W, hatch spacing 130 µm, layer thickness 25 µm, scanning speed 500 mm/s, chessboard bidirectional scanning strategy.
  Heat treatment: Solution-treated at 550 °C for 2 h, followed by furnace cooling.
  Laser surface remelting treatment: Laser power 20 W, beam diameter 32 µm, scanning speed 300 mm/s, layer thickness 0.01 mm.Tensile, Hardness, Roughness

  • The surface roughness of the laser surface remelted samples was significantly reduced (0.93 µm) compared to the as-built samples (19.3 µm).

  • The yield strength reduced from 200 MPa in the as-built samples to 100 MPa in the heat-treated samples.

  • The laser surface remelting process improved the microhardness by 19.5% through refining the microstructure.

  Renishaw AM250[63]Hatamleh et al. ()A357Heat treated at 170 °C for 3 h.
  Laser shock peening applied.Finite element analysis, residual stress analysis, tensile testing

  • Laser shock peening induced tensile residual stresses within certain regions of the samples.

  • Tensile tests were conducted, and the results were evaluated with finite element analysis by using Johnson-Cook parameters.

  -[64]Hitzler et al. ()AlSi10Mg Tensile

  • Post heat-treatment resulted in homogeneous microstructure, thereby exhibiting remarkable improvement in ductility.

  SLM 280HL machine[65]Hitzler et al. ()AlSi10MgLaser power 350 W, hatch spacing 0.42 mm, scan speeds 600&#;930 mm/s, base plate heating 200 °C.
  Build orientation: horizontal, inclined (45°), and vertical.Fracture toughness

  • The fracture toughness was found to be 40.63 KMPa.m0.5.

  • The vertical-built samples were found to have poor fracture toughness.

  SLM 280HL machine[66]Hitzler et al. ()AlSi10MgLaser power 350 W, hatch spacing 0.42 mm, scan speeds 600&#;930 mm/s, base plate heating 200 °C, nitrogen atmosphere.Tensile, surface hardness

  • The elastic modulus, tensile strength, and elongation were found to be sensitive to the part print orientation.

  • For the non-heat-treated condition, the Young&#;s modulus varied from 62.5 to 72.9 GPa, the Poisson&#;s ratio ranged from 0.29 to 0.36, UTS from 314 MPa to 399 MPa, and elongation from 3.2% to 6.5%.

  • The heat-treated samples exhibited dissimilar responses to an additional aging procedure and were dependent on the build height.

  SLM 280HL machine[67]Hitzler et al. ()AlSi10MgLaser power 400 W, layer thickness 50 µm, nitrogen atmosphere.Tensile, compression

  • Young&#;s modulus of the printed samples exceeded the nominal value of &#;70 GPa.

  • Vertical-built samples showed the least elastic modulus.

  • A maximum compressive strength value of 530 MPa was attained.

  SLM 280HL machine[68]Hu et al. ()AlSi10MgLaser energy input 700&#; J/m, layer thickness 50 µm, argon atmosphere.CFD model, thermal gradient

  • The results show that the temperature and molten pool depth gradually increases with new layers and energy input.

  • The cooling rate increases progressively while the solidification morphology parameter decreases with the increase of energy input.

  • The increase in energy input lead to non-linear increase in melt pool depth and remelting depth.

  -[69]Iturrioz et al. ()AlSi10MgLaser power 400 W, protective atmosphere.
  Heat treatment: Stress-relieving (heating rate of 10 °C/min until 300 °C for 2 h), Solution-treated at 450 °C and 550 °C for 2 h, followed by water quenching, and T6 heat treatment.Tensile, hardness, density

  • The as-built samples achieved a relative density of 99.9%. After heat treatments, Si forms polygonal precipitates whose size increases as the temperature increases. This results in a decrease in tensile strength and hardness with heating up to 450 °C.

  • T6 heat treatment (550 °C for 2 h followed by ageing at 180 °C for 12 h) was found to be best performing, which yielded the tensile strength of 307 ± 8 MPa, hardness 101 ± 4 HV and ductility 9 ± 3%.

  SLM 280HL machine[70]Jawade et al. ()AlSi10MgLaser power 250 W, beam diameter 0.2 mm, layer thickness 50 µm, scanning speed 500 mm/s. Tensile

  • The horizontal build orientation yielded better tensile strength when compared to samples built in the vertical orientation. Furthermore, microstructure revealed anisotropy and its dependency on build orientation.

  • The UTS was found to be maximum on horizontal orientation (401.89 MPa), yield strength (301.26 MPa) and elongation of 4.3%, which is superior than the counterpart at vertical orientation.

  Renishaw AM 250[71]Jiang et al. ()AlSi10Mg compositeLaser power 370 W, scan speed ranging from 900&#; mm/s, scan spacing 105 µm, layer thickness 30 µm, zigzag scan strategy. Tensile, hardness, density

  • The hardness and tensile strength improved by approx. 10% and 20%, respectively, with the addition of 1 wt% CNTs.

  Concept Laser M2 Cusing SLM system [72]Jing et al. ()AlSi10MgHatch spacing 190 µm, layer thickness 30 µm, volume energy density 26&#;54 Jmm&#;3, laser power 310&#;390 W, scanning speed &#; mm/s, chamber pressure 0.45 mbar.
  Build orientation: Horizontal and Vertical.Porosity, microhardness, tensile testing and fracture morphology

  • Microstructure of the samples printed using optimised process parameters consisted of extremely fine Al-Si eutectic dispersed within primary α-Al dendrites.

  • Hardness in the transverse direction was higher than that along the longitudinal direction.

  • The engineering stress-strain curve at different orientations also shows anisotropy in the strength and ductility, which is possibly due to the orientation between the tensile stress and crystal growth direction.

  EOS 83 M290 SLM[73]Kang et al. ()AlSi12Laser power 400 W, scanning speed mm/s, layer thickness 50 µm and hatch distance 45 µm.Tensile

  • Ultrafine microstructure consisting of cellular α-Al and nano-sized Si particles was found due to the high cooling rate of the SLM process

  • As the laser scanning speed increases, both tensile strength and ductility of SLM processed samples decrease.

  • Higher energy density was required to fabricate dense samples from in-situ SLM fabrication using elemental Al and Si powders, compared to pre-alloyed Al-12Si powders.

  Realizer SLM 250 machine[74]Kempen et al. ()AlSi10Mg200 W fiber laser, laser beam diameter 150 µm, scan speed mm/s, scan spacing 105 µm.
  Build orientation: Horizontal and Vertical.Tensile

  • Mechanical properties of printed parts comparable or even exceeding those of conventionally cast AlSi10Mg.

  • Maximum UTS observed for vertical samples 396 ± 8 MPa, but the elongation was better for the horizontal orientation 5.55 ± 0.4%.

  Modified Concept Laser M1 SLM Machine[4]Kempen et al. ()AlSi10MgLaser power 300 W, laser spot size 80 µm, scan speed mm/s.
  Build orientation: XY and Z.Surface roughness, Metrology

  • Samples printed in the Z-orientation has to be compensated for the width of the melt pool.

  • Samples printed in the XY-orientation showed dross formation.

  In-house built SLM machine[75]Kempen et al. ()AlSi10Mg200 W fiber laser, laser beam diameter 150 µm, scan speed mm/s, scan spacing 105 µm and layer thickness 30 µm.
  Build orientation: Horizontal and Vertical.Tensile, Hardness

  • Mechanical properties of printed parts comparable or even exceeding those of high pressure die cast AlSi10Mg.

  • Hardness found to be 152 ± 5 HV after ageing at 175 °C for 6 h.

  Modified Concept Laser M1 SLM Machine[76]Kempen et al. ()AlSi10Mg170 to 200 W fiber laser, laser beam diameter 150 µm, scan speed 200&#; mm/s, scan spacing 105 µm and layer thickness 30 µm.
  Build orientation: Horizontal and Vertical.Density, Roughness

  • Narrow process window to obtain optimal density and surface quality for printed parts.

  • Higher scan speed of mm/s was used for high density/productivity demands, whereas lower scan speeds of &#; mm/s were used for parts with a high demand in top surface quality.

  Modified Concept Laser M1 SLM Machine[77]Kim et al. ()AlSi10MgLaser power 200 W, scanning speed mm/s, bidirectional scanning vector.Tensile

  • Significant stress partitioning exists between the Si (680 MPa) and Al (260 MPa) constituents.

  • The fracture analysis reveals large voids and cracks in the microstructure, particularly in the soft Al matrix under loading.

  Concept Laser M2 machine[78]Kimura and Nakamoto ()A356Laser power 200&#;370 W, scan speed 400&#; mm/s, scan spacing 0.08&#;0.18 mm, layer thickness of 30 µm.Tensile, Density

  • Relative density of 99.8% could be obtained by optimizing the laser irradiation conditions.

  • Tensile strength of 400 MPa, yield strength of 200 MPa, and elongation of 12&#;17% was obtained for optimally printed samples.

  • After annealing the UTS reduced to 250 MPa and yield strength to 125 MPa, however, elongation increased to 30%.

  EOSINT M280 SLM [20]Krishnan et al. ()AlSi10Mg200 W Yb fiber laser, layer thickness 20&#;40 µm, beam diameter 0.1 mm, laser power 180&#;195 W, scanning speed 700&#;900 mm/s, hatch distance 0.1&#;0.25 mm, nitrogen atmosphere.Hardness, Density

  • Hatch distance is the most influential process parameter affecting the print part density.

  • There is a close correlation between the geometry of scan tracks and macroscopic properties of the printed parts.

  • The optimal energy density was found to be 1.2&#;1.8 J/mm2.

  -[79]Li et al. ()AlSi10MgLaser power 350 W, beam diameter 80 µm, scan speed mm/s, layer thickness 50 µm, scan spacing 170 µm, argon chamber atmosphere, substrate plate pre-heated to 100 °C.
  Heat treatment: T6 treatment, solution treated at 450 °C, 500 °C, and 550 °C for 2 h, water quenched, and aged at 180 °C for 12 h.Tensile, hardness

  • The solubility of Si in the Al matrix of the as-built samples was found to be about 8.89 at%, which significantly decreased after solution heat treatment, and further decreased with ageing treatment.

  • The tensile strength decreased from 434.25 ± 10.7 MPa for the as-built specimens to 168.11 ± 2.4 MPa for the specimens that were solution heat-treated only. However, the fracture strain increased from 5.3 ± 0.22% to 23.7 ± 0.84%.

  SLM250 HL[80]Li et al. ()AlSi10MgBuild orientation: Horizontal (Y-direction) and Vertical (Z-direction), tensile testing carried out at &#;71 °C. Tensile

  • The tensile strength and elongation of the horizontally-built samples are 340 MPa and 11.2%, respectively, compared to 350 MPa and 13.4%, respectively, for the vertically-built samples.

  • The microstructure revealed fish-scale morphology along the Y-build direction and oval shaped structure in the Z-build direction.

  -[81]Li et al. ()AlSi12Laser power 200 W, scanning speed 500 mm/s, layer thickness 50 µm, scan spacing 150 µm, substrate heated to 200 °C, argon atmosphere.
  Heat treatment: Solution treated at 500 °C for 4 h and water quenched.Tensile, residual stresses, FEM

  • Spherical Si particles with size less than 100 nm formed at the Al grain boundaries. However, the coarse and fine Si precipitates were found to be homogeneously distributed in the Al matrix.

  • The ultrafine eutectic microstructure yields significantly better tensile properties and an extremely high ductility of approx. 25% after solution heat treatment.

  ReaLizer SLM-100 machine[82]Li et al. ()AlSi10MgLaser power 200 W, hatch spacing 80 µm, laser spot diameter 80 µm, layer thickness 25 µm, exposure time 100&#;180 µs, point distance 60&#;100 µm.Modelling and simulation

  • A 3D FE model was developed to simulate the thermal behaviour and melt pool dimensions of the printed parts.

  • The cooling rate of the melt pool reduced from 7.93 × 106 °C/s to 3.61 × 106 °C/s as the laser exposure time is increased from 100 µs to 180 µs. Alternatively, with an increase in point distance from 60 µm to 100 µm, the cooling rate increased from 3.25 × 106 °C/s to 7.48 × 106 °C/s.

  • The melt pool size (width and depth) increased as the laser exposure time is increased, and vice-versa when the point distance is increased.

  Renishaw AM 400 SLM system (Renishaw PLC)[83]Li and Gu ()AlSi10MgLaser power of 150&#;300 W, laser spot diameter 70 µm, scanning speed 100&#;400 mm/s, layer thickness 50 µm, hatch spacing 50 µm, argon atmosphere.Modelling and simulation

  • SLM experimental results validated the obtained thermal behavior in simulation.

  • The cooling rate increased from 2.13 × 106 °C/s to 2.97 × 106 °C/s when the laser power was increased from 150 W to 300 W, and from 1.25 × 106 °C/s to 6.17 × 106 °C/s when the scan speed increased from 100 mm/s to 400 mm/s.

  • A sound metallurgical bonding between the neighboring layers was obtained at the optimized combination of process parameters, including laser power of 250 W and scan speed of 200 mm/s.

  YLR-500-SM[84]Liu et al. ()AlSi10MgLaser power 200 WTensile, hardness, density, roughness

  • An 80% decrease in surface roughness was observed when the printed parts were sand blasted.

  • The tensile properties of the as-built samples tested at both room temperature and high temperature (200 °C) are significantly better than the conventionally heat-treated cast parts.

  M2 Cusing from Concept Laser, Germany[85]Liu et al. ()AlSi10MgLaser power 500 W, scan speed mm/s, layer thickness 30 µm, zigzag scan strategy, scanning angle alternated by 90° for subsequent layers.Hardness, wear resistance, modelling and simulation

  • The cooling rate for the layers printed at the top region of the sample was determined to be about 1.44 × 106 K/s, which is significantly higher than that experienced by the bottom layers (&#; 1 × 103 K/s).

  • The top surface area has a lower degree of crystallinity of Al matrix than that of core area.

  • The surfaces of the printed samples exhibited higher hardness and wear resistance compared to the core regions.

  BLT-S300 SLM machine[86]Liu et al. ()AlSi10MgLaser power 160&#;200 W, spot size 100 µm, scanning speed 200&#; mm/s, argon atmosphere.Modelling and simulation

  • The cooling rate, temperature gradient and the solidification rate increase with an increase in laser power and decrease with an increase in scanning speed.

  • Along Z direction, the cooling rates and the temperature gradient are lower compared to Y direction.

  IPG YLR-200[87]Louvis et al. ()AA Laser power 50&#;100 W, laser spot size 80 µm, hatch spacing 0.05&#;0.3 mm, scan speed range 75&#; mm/s, layer thickness 50 µm, argon atmosphere, point distance 65&#;85 µmDensity

  • The formation of oxides can be avoided by using high laser powers while printing.

  • The maximum relative density was obtained at high laser power of 100 W (89.5%).

  MCP Realizer 100 SLM machine[8]Maamoun et al. ()AlSi10Mg & AA For AA : Laser power 300&#;370 W), scanning speed 800&#; mm/s, hatch spacing 0.1&#;0.19 mm, energy density 40.5&#;123.3 J/mm3.
  For AlSi10Mg: Laser power 200&#;370 W), scanning speed &#; mm/s, hatch spacing 0.15&#;0.25 mm, energy density 27&#;65 J/mm3. Tensile, hardness

  • The microstructure of AA parts did not show the same fibrous Si network that formed inside the AlSi10Mg microstructure due to lower Si content.

  • The size of the melt pool increases with an increase in energy density. An energy density range of 50 to 60 J/mm3 was found to be optimum to significantly minimize the formation of keyhole defects and porosities.

  • Maximum tensile strength of both the AlSi10Mg and AA printed samples was 396.5 MPa.

  -[88]Maconachie et al. ()AlSi10MgLaser power 350 W, scanning speed mm/s, layer thickness 30 µm, hatch spacing 130 µm and beam diameter 90 µm.
  Build Orientation: 0°, 45° and 90°. Tensile, dynamic behaviour in tension (SHTB), fracture

  • The tensile strength is not significantly affected by the build orientation of the printed samples.

  • Samples built perpendicular to the build direction failed at greater strain than those built parallel to the build direction.

  • The anisotropic properties of the samples were insensitive to the strain rate applied during mechanical testing.

  SLM500[89]Majeed et al. ()AlSi10MgLaser power 320 W, hatch spacing 0.08 mm, layer thickness 30 µm, scanning speed 900 mm/s, checkerboard scanning strategy, argon atmosphere.
  Heat Treatment: T4 treatment involving solution heat treated at 530 or 540 °C for 2 h and water quenched. T6 treatment involving solution treated at 530 °C for 2 h, water quenched and artificially aged at 155 °C for 12 h.Density, tensile, fracture

  • As the wall thickness increased from 0.5 mm to 1.5 mm, an increase in porosity was observed.

  • Ageing heat treatment resulted in better density of the thin wall samples.

  • The size of the pores increased till the wall thickness of 1.5 mm and then decreased with further increase in wall thickness.

  280 HL SLM[90]Maskery et al. ()AlSi10MgLaser power 200 W, layer thickness 25 µm, hatch spacing 130 µm, scanning speed 571 mm/s, point distance 80 µm, exposure time 140 µs, build platform temperature 180 °C, hatch rotation 67°.
  Heat treatment: Solution treated at 520 °C for 1 h, water quenched, and aged at 160 °C for 6 h.Tensile, fatigue

  • The elongation at break for the heat-treated material was nearly three times greater than that observed for the as-built material, and the fatigue strength at 106 cycles was around 1.6 times as high.

  • The UTS was reduced from 330 ± 10 MPa to 292 ± 4 MPa and the ductility enhanced from (1.4 ± 0.3)% to (3.9 ± 0.5)%.

  Renishaw AM250 SLM machine[91]Mfusi et al. ()AlSi10MgLaser power 150 W, scanning speed mm/s, hatch spacing 50 µm, and layer thickness 50 µm.
  Build Orientation: XY, 45°, and Z orientations.
  Heat treatment: Stress relief treatment at 300 °C for 2 h followed by furnace cooling.Tensile, fatigue crack growth, fracture toughness, density, hardness, porosity

  • Anisotropy due to different build orientations was found even after post stress relief heat treatment.

  • Maximum relative density was reported for XY printed samples (97.33 ± 0.92%). However, maximum hardness was reported for the 45° orientation printed samples (47.32 ± 3.35 HV).

  SLM Solution M280 GmbH[92]Ngnekou et al. ()AlSi10MgLaser powers 200 W and 400 W.
  Build Orientation: XY and Z
  Heat treatment: Stress relieved at 160 °C for 1 h or 300 °C for 2 h, T6 heat treatment involving solution treated at 540 °C for 8 h, water quenched, and tempered at either 20 °C for 24 h or 160 °C for 10 h.Fatigue

  • The improvement in fatigue resistance is less pronounced when large-sized defects are present in the printed samples.

  • There is no influence of the defect type on the fatigue limit.

  Phenix PM100 3D Systems machine
  EOS M290 machine [93]Nurel et al. ()AlSi10MgLaser power 400 W, spot diameter 80 µm, scan velocity mm/s, strip scanning strategy, hatch distance 200 µm, hatch rotation 67°, layer thickness 60 µm, argon atmosphere, build plate temperature 35 °C.
  Build orientation: Horizontal and Vertical
  Heat Treatment: T5/Stress relief treated at 300 °C for 2 h.Dynamic-Compression

  • The dynamic anisotropic properties were insensitive to variation in strain rates.

  • Anisotropic differences were considerably reduced by applying T5 heat treatment.

  • The as-built samples failed after SHPB tests which was observed in the T5 heat treated samples.

  EOSINT M280 system[94]Nurel et al. ()AlSi10MgLaser power 400 W, spot diameter 80 µm, layer thickness 30 µm.
  Build orientation: Horizontal and Vertical.
  Heat treatment: T5 at 300 °C for 2 h.Dynamic-Compression

  • No strain sensitivity was observed.

  • True stress for as-built and heat-treated conditions are 569 ± 8.5 MPa and 427 ± 4.8 MPa respectively.

  EOSINT M280 system[95]Ojha et al. ()AlSi10MgLaser power 100 W, scanning speed mm/s, spot size 0.2 mm, layer thickness 80 µm.Modelling and simulation

  • FEA was carried out to investigate temperature evolution, heat transfer and solidification process.

  • Simulation results are dependent on process parameters along with material properties.

  -[96]Pei et al. ()AlSi10MgLaser power 180 W, scanning speed 600&#; mm/s, layer thickness 35 µm, spot size 70 µm.Modelling and simulation

  • The perturbation or the instability within the molten pool results in the formation of pores during SLM, which have a direct influence on the densification level.

  • At high scanning speed, the track morphology became discontinuous leading to poor bonding and balling.

  SLM-150 equipment[97]Pola et al. ()AlSi10Mg-Fatigue, porosity, surface roughness, tensile

  • Post-treatment is effective in reducing surface roughness and inducing compressive residual stresses on the material surface.

  • Sand blasting had a beneficial effect of the fatigue resistance.

  EOS M290 system[98]Ponnusamy et al. ()AlSi12Laser power 285 W, scanning speed mm/s, hatch spacing 100 µm, layer thickness 40 µm, defocus distance &#;4 mm, alternative scan strategy.
  Build orientation: Horizontal, Inclined, VerticalDynamic - Compression

  • The dynamic compressive strength increased with an increase in the angle of print orientation, i.e., from 0° to 90°.

  • The yield strength and compressive strength decrease for printed samples tested at elevated temperature of 200 °C.

  • The flow stress was found to be higher for dynamic loading compared to quasi-static loading at elevated temperature.

  3D Systems ProX 200[99]Ponnusamy et al. ()AlSi12Laser power 285 W, scanning speed mm/s, hatch spacing 100 µm, layer thickness 40 µm, defocus distance &#;4 mm, alternative scan strategy, hexagon scan pattern, argon atmosphere.
  Build orientation: Vertical
  Heat treatment: Annealed at 200 °C and 400 °C for 3 hrs.Dynamic compression

  • Thermal softening was observed in printed samples tested at elevated temperatures, which resulted in significant reduction in flow stress.

  • A 20% and 50% reduction in flow stress was observed when samples were tested at 200 °C and 400 °C test temperatures, respectively.

  • A 12% and 45% reduction in flow stress was observed for samples heat treated at 200 °C and 400 °C, respectively, and then tested.

  ProX 200[100]Prashanth et al. ()AlSi12Laser power 320 W, layer thickness 50 µm, hatch spacing 110 µm, hatch rotation 73°, scanning speed &#; mm/s, argon atmosphere.
  Build orientation: 30°, 45°, 60°, 75°, 90°.
  Heat treatment: Solution treated at 473&#;723 K for 6 h.Wear rate, corrosion properties

  • As-built samples exhibit better wear resistance and similar corrosion resistance compared to cast counterparts.

  • Both wear and corrosion properties deteriorated with annealing post heat treatment, due to growth of Si precipitates.

  SLM 250 HL[16]Prashanth et al. ()AlSi12Laser power 320 W, layer thickness 50 µm, hatch spacing 110 µm, hatch rotation 73°, scanning speed &#; mm/s, argon atmosphere, scan strategies included single melt, double melt, single melt continuous, and checkerboard, base plate heating 473&#;673 K.
  Heat treatment: Solution treated at 473&#;723 K for 6 h.Tensile

  • The difference in tensile properties were attributed to the variation in crack propagation path.

  • The samples printed without contour exhibited significant increase in ductility without compromising on the tensile strength.

  • The results indicate that the room temperature tensile properties can be tuned (between YS: 115&#;290 MPa, UTS: 220&#;460 MPa and ductility: 2.8&#;9.5%) in-situ with appropriate selection of process parameters.

  SLM 250 HL[101]Prashanth et al. ()AlSi12Laser power 320 W, layer thickness 50 µm, hatch spacing 110 µm, hatch rotation 73°, scanning speed &#; mm/s, argon atmosphere.
  Build orientation: 30°, 45°, 60°, 75°, 90°.
  Heat treatment: Solution treated at 473&#;723 K for 6 h.Tensile

  • The Al and Si phases show remarkably small crystallite sizes of about 118 and 8 nm.

  • The as-built samples exhibited a yield strength of 260 MPa and tensile strength of 380 MPa, which was significantly higher than the cast counterparts.

  • The texture of the microstructure of the printed samples varied with variation in build orientations, however, this did not affect the tensile properties.

  SLM 250 HL[17]Qiu et al. ()AlSi10MgLaser power 150&#;400 W, beam spot size 50 µm, scanning speed &#; mm/s. Compression

  • The dimensions of the melt pool increased with an increase in laser power resulting in strut diameters deviating from the designed values.

  • The compressive load bearing capacity of the lattice structures increased with an increase in strut diameter.

  • Deformation of lattice structures occurred by homogeneous deformation until the maximum stress was achieved after which the structure lost structural integrity via a series of shear banding events at around 45° to the compression axis.

  Concept Laser M2 Cusing SLM system[102]Rakesh et al. ()AlSi10MgLaser beam diameter 80 µm, argon/nitrogen gas inert atmosphere.
  Build orientation: Transverse (XZ), Longitudinal (Y)Tensile, Impact strength

  • Printed samples displayed superior tensile strength (~350 MPa) and impact strength compared to cast parts.

  • Significant improvements in tensile properties and impact energies were observed in the transversely-built samples irrespective of the chamber atmosphere.

  EOSINT M280 machine[103]Rao et al. ()A357Laser power 100&#;370 W, layer thickness 30 µm, hatch distance 0.1 mm, spot size diameter 0.1 mm, scan speed 500&#; mm/s, substrate temperature 35&#;200 °C.
  Build orientation: Horizontal, Vertical.Tensile

  • The mechanical property was largely affected by different substrate temperatures.

  • The coarse Si precipitates formed along the build direction facilitates intercellular failure, resulting in poor tensile properties.

  EOSINT M280[25]Rao et al. ()A357Laser power 100&#;370 W, layer thickness 30 µm, hatch distance 0.1 mm, spot size diameter 0.1 mm, scan speed 500&#; mm/s, substrate temperature 35&#;200 °C.
  Heat treatment: Stress relieving at 300 ± 1 °C and air-cooled, solution treating at 535 ± 3 °C in salt bath from 0.25 h to 150 h followed by water quenching.Tensile

  • The as-built samples had an ultrafine microstructure, with high residual stresses and non-equilibrium solid solute concentration of Si in the supersaturated Al matrix.

  • The tensile properties of the printed A357 samples were comparable or better than the traditional cast counterparts.

  • The UTS and YS of as-built sample are 426.4 ± 2.6 MPa and 279.6 ± 1, respectively, however, the ductility was found to improve after stress-relieving (13.6 ± 0.6%).

  EOSINT M280[24]Rashid et al. ()AlSi12Laser power 285 W, scan speed &#; mm/s, layer thickness 40 µm, hatch distance 100 µm, defocus distance &#;4 mm.
  Build orientation: Horizontal, Inclined (45°), VerticalTensile, density

  • Energy per layer in the range of 504&#;895 J yielded &#; 99.8% relatively dense AlSi12 SLM-printed samples.

  • Yield strength range 225&#;263 MPa, tensile strength range 260&#;365 MPa, and ductility range 1&#;4% was found for the printed samples with different build orientations.

  • Anisotropy in mechanical properties was attributed to differences in relative densities.

  ProX 200[104]Rashid et al. ()AlSi12Laser power 285 W, scan speed &#; mm/s, layer thickness 40 µm, hatch distance 100 µm, defocus distance &#;4 mm.
  Lattice structures: Circular cells, honeycomb cells, triangular cellsFlexural

  • The printed samples exhibited brittle failure.

  • Triangular lattice structure had the highest flexural strength of 175.80 ± 1 MPa, circular 151.35 ± 0.67 MPa, and honeycomb 143.16 ± 3.85 MPa, whereas the solid specimen had a strength of 290 ± 26 MPa.

  • Triangular lattice structure showed good flexural modulus of 5 GPa compared to the honeycomb structure (4.34 GPa) and circular structure (4.37 GPa).

  ProX 200[105]Rathod et al. ()AlSi12Laser power 320 W, scan speed mm/s, layer thickness 50 µm, and hatch spacing 110 µm.Wear

  • Printed samples displayed significant anisotropy in wear rate due to change in laser track orientation.

  • Porosity significantly affected the wear rate.

  280HL equipment [106]Raus et al. ()AlSi10MgLaser spot size 80 µm, laser power 350 W, scan speed mm/s, layer thickness 30 µm, hatch distance 0.13 mm, stripe scanning strategy, argon atmosphere, build platform temperature 150 °C.Tensile, hardness, impact toughness

  • Porosities of the order of 5 to 20 µm were observed in relatively dense (99.13%) sample.

  • Printed samples displayed higher mechanical properties compared to high pressure die cast samples.

  SLM 125 HL[107]Read et al. ()AlSi10MgLaser power 100&#;200 W, laser track width 150 µm, layer thickness 30 µm, scan speed 700&#; mm/s, hatch spacing 0.2&#;0.8 mm, island scanning strategy, island size 2&#;8 mm, argon atmosphere.
  Build orientation: Horizontal, Vertical.Tensile, creep resistance

  • A critical energy density of 60 J/mm3 was found wherein minimum pore fraction was observed.

  • Creep results showed better rupture life than cast alloy, displaying good agreement with the Larson&#;Miller literature data.

  • Unmelted powder particles give rise to local cracking, as observed on the fracture surfaces.

  Concept Laser M2 Cusing SLM system[108]Rosenthal et al. ()AlSi10MgLaser power 400 W, laser spot size 100 µm, scan velocity mm/s, strip scanning strategy, hatch rotation 67°.Tensile, density

  • The mechanical properties of the printed parts displayed a strong dependency on the microstructure and are comparable or higher than cast part after T6 heat treatment.

  EOSINT M280[109]Rosenthal et al. ()AlSi10MgLaser power 400 W, laser spot size 100 µm, scan velocity mm/s, hatch distance 200 µm, layer thickness 60 µm, argon atmosphere.
  Build orientation: Horizontal (X), Vertical (Z).
  Heat Treatment: T5 stress relief treatment at 300 °C for 2 h, modified T5 at 200 °C for 2 h.Impact resistance

  • Horizontally built specimens absorbed more impact energy compared to vertically built specimens.

  EOSINT M280[110]Rosenthal and Stern ()AlSi10MgLaser power 400 W, laser spot size 100 µm, scan velocity mm/s, hatch distance 200 µm, layer thickness 60 µm.
  Heat treatment: Treated at 100&#;250 °C for 2 h, treated at 200 °C for 168 h, treated at 100 °C for 336 h.Hardness

  • Results revealed that the heat treatments conducted in the range of 100 °C&#;300 °C displayed noticeable increase in hardness values due to precipitation/coarsening of the Si phase.

  EOSINT M280[111]Rosenthal et al. ()AlSi10MgLaser power 400 W, scanning speed mm/s, strip scanning strategy
  Build orientation: Vertical, Horizontal.
  Heat treatment: Stress relieving at 300 °C for 2 h.Tensile, hardness, fracture morphology

  • The printed parts displayed room temperature mechanical properties comparable or even exceeding conventionally cast AlSi10Mg samples.

  • In the vertical orientation, the samples display Young&#;s modulus of 69.5 to 73 GPa, yield strength 167&#;170 MPa, UTS 269&#;277 MPa and elongation ranging 7.8&#;8.7%, whereas in the horizontal orientation Young&#;s Modulus ranges between 69&#;71.3 GPa, yield strength 168&#;170 MPa, UTS of 267 MPa and elongation ranging 8.6&#;9.5%.

  -[112]Rosenthal et al. ()AlSi10MgLaser power 400 W, laser spot size 100 µm, scan velocity mm/s, hatch distance 200 µm, layer thickness 60 µm, argon atmosphere, build plate temperature 35 °C, strip scanning strategy, hatch rotation 67°.
  Build orientation: Vertical, Horizontal.Tensile, fracture surface analysis

  • Printed samples were sensitive to strain rate variations with significant changes to the flow stress and strain hardening exponents with an increase in strain rate.

  • The strain rate sensitivity was similar in both vertical and horizontally printed samples, while the true strain was significantly higher in the samples built in the horizontal orientation.

  EOSINT M280[113]Samantaray et al. ()AlSi10MgLaser power ranging 70&#;190 W, laser spot diameter 0.2 mm, scanning speed 100&#;500 mm/s, layer thickness 1 mm.Modelling and simulation

  • The maximum temperature of the molten pool increased from 731 °C to °C and the molten pool length changed from 0.286 mm to 2.167 mm, when the laser power increased from 70 W to 190 W.

  • The sintering depth of the powder layer increased with an increase in laser power but decreased when the scan speed was increased.

  -[114]Siddique et al. ()AlSi12Laser power 400 W, volume energy density 39.6 J/mm3, argon atmosphere.
  Heat treatment: Stress relieving at 240 °C for 2 h followed by oven cooling.Fatigue, tensile

  • The microstructure of the printed samples consisted of fine grains and precipitates that resulted in increased quasi-static strength compared to that of the cast counterparts.

  • The fatigue strength of the as-built hybrid samples was comparably better than the as-built samples.

  SLM 250[115]Siddique et al. ()AlSi12Laser power 350 W, scan speed 930 mm/s, hatch distance 0.19&#;0.25 mm, energy density 20&#;39.6 J/mm3, argon atmosphere.
  Heat treatment: Stress relieving at 200 °C followed by oven cooling.Fatigue, porosity, modelling and simulation

  • Similar porosity percentage was found using optical microscopy and X-ray computed tomography techniques.

  • Hot isostatic pressing post treatment resulted in reduction of strength, however, was comparable to that of the die-cast parts.

  • Even smaller size pores present in the vicinity of the surface of the fatigue samples, significantly contributed to the decrease in fatigue life. This surface weakness effect was mitigated by the hot isostatic pressing post treatment.

  SLM 250 HL[116]Siddique et al. ()AlSi12Laser power 350 W, scan speed 930 mm/s, hatch spacing 0.19 mm, layer thickness 50 µm, energy density 39.6 J/mm3, scanning strategy chessboard, hatch rotation 79°, argon atmosphere, base plate temperature 200 °C.
  Build orientation: Vertical.
  Heat treatment: Stress relieving at 200 °C for 2 h.Fatigue, porosity, hardness, crack propagation testing

  • Stress relief post heat treatment at 240 °C caused an increase in porosity due to the growth of pores.

  • At low stresses, the samples printed with base plate heating displayed higher fatigue performance compared to the samples printed without base plate heating.

  • Samples printed without base plate heating consisted of higher porosity, which facilitated samples failing from cracking due to defects. Such an occurrence was significantly reduced in samples printed with base plate heating.

  SLM 250 HL[14]Siddique et al. ()AlSi12Laser power of 400 W, energy density 20&#;39.6 J/mm3, chessboard scanning strategy, hatch rotation 79°, argon atmosphere, base plate temperature 200 °C.
  Build orientation: Vertical.
  Heat treatment: Stress relieving at 240 °C followed by oven cooling.Tensile, surface roughness, residual stress analysis, fatigue

  • Base plate heating induces a coarser grain microstructure in the printed samples owing to a decrease in cooling rate.

  • Tensile strength of the printed samples was four times that of sand-cast parts and two times that of die-cast parts.

  • Significant reduction in residual stresses was observed in samples printed with base plate heating, which also reduced the scatter in fatigue data.

  SLM 250 HL[15]Silvestri et al. ()AlSi10MgEOS M400: Laser power W, laser spot diameter 90 µm, nitrogen atmosphere.
  SLM 280: Laser power 400&#; W, laser spot diameter 80&#;225 µm, argon atmosphere.
  Renishaw AM400: Laser power 400 W, laser spot diameter 70 µm, argon atmosphere.
  Build orientation: 0°, 60°, 90°.Tensile

  • The mechanical properties of the samples printed using different SLM machines were different, even though the best process parameters suggested by the equipment manufacturers were employed.

  EOS M400
  SLM 280
  Renishaw AM400[117]Subbiah et al. ()AlSi10MgLaser power 350 W, laser spot size 0.2 mm, scanning speed 730 mm/s, hatch spacing 0.12 mm, layer thickness 30 µm, stripe scanning strategy, inert atmosphere, base plate temperature 150 °C.
  Heat treatment: Solution treated at 550 °C for 2 h and water quenched.Tensile, surface roughness, modelling and simulation

  • The microstructural studies revealed that the samples were stretched due to the exclusion of Si enriched cellular and dendritic network.

  • Printed samples exhibited high tensile strength of 431 MPa.

  SLM 280 HL[118]Sun et al. ()AlSi10MgLaser power 400 W, laser spot size 100 µm, scanning speed mm/s, hatch spacing 0.165 mm, layer thickness 25 µm, chessboard scanning strategy, hatch rotation 67°.
  Heat Treatment: T2 treatment&#;annealed at 380 °C for 45 mins and air cooled, T6-like treatment&#;solution treated at 500 °C for 15 mins, quenched, and aged at 158 °C for 10 mins.Tensile

  • A homogeneous distribution of spheroidised Si was observed in heat treated parts.

  • It was suspected that Si experienced the necking effect under a tensile environment due to the large temperature gradient and α-Al erosion during the SLM process.

  • The tensile strength of the as-built samples was better than the as-cast samples, however, the strength reduced with subsequent post heat treatment.

  Renishaw AM 250[119]Suryawanshi et al. ()AlSi12Laser power 320 W, layer thickness 50 µm, hatch spacing 110 µm, hatch rotation 73°, scanning speed ( mm/s for volume and mm/s for contour), argon atmosphere, single melt and checkerboard scanning strategy.
  Heat treatment: solution treated at 573 K for 6 h.Tensile, fracture toughness, fatigue crack growth

  • The fatigue crack growth threshold and unnotched fatigue strength of SLM alloys was inferior compared to cast alloys, which could be attributed to tensile residual stresses, shrinkage porosity, and un-melted particles.

  • The printed samples exhibited enhanced toughness due to the presence of mesostructure Si.

  • Toughness was found to be sensitive to crack orientation with respect to the build and scan orientations.

  SLM 250 HL[120]Takata et al. ()AlSi10MgLaser power 380 W, layer thickness 30 µm, hatch spacing 0.1 mm, hatch rotation 67°, argon atmosphere.
  Build orientation: Horizontal (X/Y), Vertical (Z).
  Heat treatment: Annealing at 300 °C for 2 h, or solution treatment at 530 °C for 6 h and water quenched.Tensile

  • A fine dislocation substructure consisting of low angle boundaries was found within the α-Al grains.

  • {001} texture along the Z direction was observed which was attributed to the preferential <001> grain growth of the α-Al phase during rapid solidification.

  • The as-built samples exhibited a high tensile strength of approximately 480 MPa irrespective of the build orientation. In contrast, the ductility was direction-dependent, thereby resulting in the fracture preferentially occurring at the melt pool boundaries.

  EOSINT M 280[121]Tang and Pistorius ()AlSi10MgLaser power 370 W, scan speed mm/s, layer thickness 30 µm, laser spot diameter 100 µm, hatch spacing 0.16&#;0.22 mm, hatch rotation 67°.
  Build orientation: XY, Z.
  Heat treatment: Stress relieving at 573 K for 2 h.Tensile, fracture morphology, porosity

  • The Z-oriented samples flow at a lower imposed stress than the XY-oriented samples.

  • The maximum yield strength was noted for the XY-built samples, while maximum tensile strength was observed for the Z-built samples.

  • Variation in hatch spacing results in porosity formation in the printed parts, which subsequently reduced the tensile performance.

  EOS M280[122]Tang and Pistorius ()AlSi10MgLaser power 370 W, scan speed mm/s, laser beam diameter 0.1 mm, layer thickness 30 µm, hatch spacing 0.16&#;0.22 mm, and the
  Build orientation: XY, Z.
  Heat treatment: Stress relieving at 573 K for 2 h.Fatigue, porosity

  • A correlation between the crack-initiating pore on the fracture surface and fatigue life was established.

  • The fatigue resistance was affected by the variation in hatch spacing and build orientation.

  • XY-oriented samples have better fatigue performance, possibly due to anisotropy of pores, residual stress, and of melt-pool boundaries.

  EOS M280[123]Tradowsky et al. ()AlSi10MgLaser power 175 W, laser spot size 60 µm, scan speed mm/s, layer thickness 30 µm, scan spacing 97.5 µm, chess scanning strategy, island size 5.6 mm, argon atmosphere.
  Build orientation: Horizontal, Vertical.
  Heat treatment: Solution treated at 520 °C for 5 h, water quenched, and aged at 160 °C for 12 h followed by air cooling.Tensile, porosity, modelling and simulation

  • Columnar grains were observed along building direction, with equiaxed grains found in-cross section.

  • Irregular-shaped voids were observed in both the as-built and heat-treated conditions due to the formation of oxide layer. These pores were considerably reduced after hot isostatic pressing post treatment, however, the oxide layers remained.

  • Heat treated and hot isostatic pressed samples had tensile properties exceeding that of the cast counterparts.

  Concept Laser M2 cusing system[124]Trevisan et al. ()A357Laser power 195 W, spot size 100 µm, layer thickness 30 µm, scanning speed mm/s, hatch distance 0.1 mm, hatch rotation 67°, build plate temperature 100 °C.
  Heat treatment: Stress relieving at 300 °C for 2 h, T6 treatment involving solution treatment at 540 °C for 8 h, water quench, and ageing at 170 °C for 3 h.Tensile, hardness

  • The tensile strength decreased after stress relief heat treatment.

  • After T6 heat treatment, the microstructure became more isotropic, and the mechanical properties were comparable to that of the as-built condition.

  EOSINT M270 Dual mode machine[125]Uzan et al. ()AlSi10MgLaser power 400 W, beam diameter 100&#;150 µm, scanning speed mm/s, layer thickness 30 µm and 60 µm (before and after melting), hatch distance 200 µm, stripe scanning strategy, argon atmosphere, build plate temperature 35 °C.
  Build orientation: Z direction.
  Heat treatment: Stress relieved at 300 °C for 2 h.Fatigue, tensile, fracture toughness, hardness

  • The fatigue resistance of the as-built samples was highest and that of the stress relieved and hot isostatic pressed samples was the lowest.

  • The critical stress intensity factor can be estimated by the fracture surface morphology of the fatigue specimen.

  EOSINT M-280 [126]Vrana et al. ()AlSi10MgLaser power 150&#;400 W, layer thickness 50 µm, scanning speed &#; mm/s, nitrogen atmosphere, build platform temperature 120 °C.Impact testing

  • Lattice structures fabricated with scanning speed of 500 mm/s achieved 10× higher stiffness than those printed using mm/s for the same geometry of the unit-cell.

  • Samples printed with a laser power of 350 W and scanning speed of mm/s achieve greater geometrical stability and had better accuracy.

  SLM 280HL[127]Wang et al. ()AlSi10MgLaser power 370 W, scan speed mm/s, hatch spacing 190 µm, layer thickness 30 µm, argon atmosphere.
  Build orientation: Vertical.
  Heat treatment: Stress relieved at 250 °C for 4 h.Tensile, porosity, modelling and simulation

  • The deviation between reconstructed and as-designed models was less than 100 μm.

  • The anisotropic properties of the printed parts were attributed to the non-uniform distribution of process-induced defects within the samples, which had a deleterious effect on the tensile strength.

  • The presence of geometric defects significantly influenced the tensile strength and elongation.

  EOS M290[128]Wang et al. ()AlSi10MgLaser power 400 W, laser spot size 76 µm, scanning speed mm/s, hatch distance 175 µm, layer thickness 25 µm, chessboard scanning strategy, island size 5 mm, argon atmosphere.
  Heat treatment: T6 solution treated at 535 °C for 7&#;15 mins and aged at 158 °C for 10 h.Tensile, bending, hardness

  • A decrease of about 20% in hardness and tensile strength whereas an increase of about 155% in elongation was reported for the heat-treated samples.

  • An increase of about 123% in fracture deflection and a decrease of about 6% in bending strength was also found for the heat-treated samples.

  Renishaw AM 250[129]Wang et al. ()AlSi10MgLaser power 400 W, scanning speed mm/s, hatch spacing 175 µm, layer thickness 25 µm, chessboard scanning strategy, hatch rotation 67°.
  Build orientation: Parallel, Normal.
  Heat Treatment: T2 stress relieving treatment at 380 °C for 45 mins followed by air cooling.Tensile, bending, hardness

  • The hardness, tensile strength and bending strength decrease by about 50% after T2 heat treatment

  • The precipitates in the molten pool boundaries dissolve in the matrix after heat treatment.

  Renishaw AM 250 system[130]Wang et al. ()AlSi12Laser power 200 W, beam diameter 35 µm, scanning speed 375&#; mm/s, hatch spacing 0.15 mm, layer thickness 50 µm, stripe scanning strategy, hatch rotation 90°, inert atmosphere.Tensile, hardness

  • Insignificant differences in density and hardness was observed when the samples were printed in either argon, nitrogen, or helium chamber atmospheres.

  • The samples showed superior performance; 1.5 times yield strength, 20% higher tensile strength, and twice elongation, compared to conventionally produced material.

  Realizer SLM 100[131]Wei et al. ()AlSi10MgLaser spot size 70 µm, laser power 150&#;180 W, scanning speed 600&#; mm/s, layer thickness 40 µm, hatch spacing 50&#;70 µm, random scanning strategy, argon atmosphere.Tensile, fracture morphology

  • A linear energy density of 1.5&#;1.875 J/cm was reported to yield continuous single-track depositions.

  • The level of porosity was significantly influenced by the variation in hatch spacing.

  • The pores and un-melted particles cause reduction in tensile strength and strain.

  Self-developed SLM 150 equipment[132]Wu et al. ()AlSi10MgLaser power 175 W, scanning speed mm/s, hatch spacing 0.65 mm, island size 6 mm.Tensile, in-situ compression testing

  • Long cell-like structures are formed in the printed samples owing to the high cooling rate of the process.

  • The Al within the eutectic grows epitaxially on the pre-existing Al cell resulting in further epitaxial growth of the Al cell formed above the eutectic.

  • Si precipitates present across the Al-matrix inhibits dislocation motion within the large Al grains.

  Concept Laser M2 system[133]Yan et al. ()AlSi10MgLaser beam diameter 100 µm, laser power of 400 W, layer thickness 30 µm, argon atmosphere.Compression, computed tomography

  • Lattices with cell sizes 3&#;6.5 mm were very thin for a low volume fraction of 5%, which tended to break during printing.

  • The printed samples showed good geometric agreement with the CAD model.

  • The compressive modulus and strength of the printed samples directly proportional to the volume fraction of the lattice cells and inversely proportional to the unit cell sizes.

  EOSINT M280[134]Yang et al. ()A357Laser power 750 W, scanning speed mm/s, hatch rotation 90°, build plate temperature 35 °C.
  Build orientation: Horizontal, Vertical.
  Heat Treatment: Directly aged at 160 °C for 8 h; Stress-relieved at 300 °C for 2 h; Stress-relieved and solution treated at 543 °C for 1&#;8 h, quenched and aged at 160 °C for 8 h.Tensile, porosity

  • Anisotropy in ductility between horizontally and vertically built samples decrease with solution heat treatments carried out for longer periods of time.

  • Negligible coarsening of the columnar grains was observed for all heat treatment conditions.

  • The stress relieved sample displayed highest elongation to fracture, primarily owing to the break-up of the Si network into fully dispersed Si particles.

  Concept Laser X-line machine[26]Zaretsky et al. ()AlSi10MgBuild orientation: XY, Z.
  Heat treatment: T5 stress relieving at 300 °C for 2 h.Dynamic and quasi-static tensile

  • Fracture of the printed samples at different tensile rates reflect a change in fracture mode from rate-independent ductile mode to rate-dependent brittle mode.

  • At high plastic strain rate range, the yield strength of the printed samples was strain rate sensitive.

  EOSINT M280 system[135]Zhang et al. ()AlSi10MgLaser power 490 W, scanning speed mm/s, layer thickness 40 µm, hatch spacing 0.1 mm, hatch rotation 90°, argon atmosphere.
  Heat treatment: Stress relieved at 300 °C for 2 h; Solution treated at 530 °C for h, water quenched, and aged at 170 °C for 12 h. Fatigue, tensile

  • Heat treatment reduces fatigue property due to the coarsening of Si precipitates.

  • For most of the fractured surfaces, the crack initiation sites indicated a presence of surface or subsurface defects.

  • The as-built samples display higher fatigue property compared to heat treated samples.

  Self-developed SLM system (LSNF-2)[136]Zhou et al. ()AlSi10MgLaser power 400 W, scanning speed mm/s, layer thickness 30 µm, hatch spacing 0.19 mm.
  Heat treatment: T6 solution treated at 520 °C for 0.5&#;4 h, water quenched, and aged at 160 °C for 1&#;24 h.Hardness

  • Eutectic structure up to 4 μm in size containing tiny needle-like semi-coherent Si particles were observed within the Al cells.

  • Embedded spherical nanoscale Si particles and segregated Mg and Fe were observed along the cell and grain boundaries of primary Al. The π-Al8Si6Mg3Fe precipitates were also identified along the boundaries.

  • Peak hardening was observed after ageing at 160 °C for 6&#;10 h, and remained relatively unchanged up to 24 h treatment time.

  EOS M280[137]Zhou et al. ()AlSi10MgLaser power 300 W, scanning speed 800 mm/s, laser spot size 80 µm, hatch spacing 0.13 mm, layer thickness 30 µm, volumetric energy density 62.5 J/mm3, argon atmosphere, build plate temperature 150 °C.
  Heat treatment: Stress relieved at 300 °C for 2 h and water quenched; solution treated 535 °C for 1 h, water quenched, and aged at 190 °C for 10 h.Tensile

  • Stress relieving post heat treatment was effective for eliminating residual stresses.

  • The printed samples exhibited tensile strength of 273.2 MPa and plasticity of 15.3%.

  SLM 280 HL[138]

  Understanding die casting

  Understanding die casting

  From engine blocks to door handles, die casting is a fast, accurate, and repeatable metal production technique suitable for large or small parts. Die casting parts have an excellent surface finish, and the process is compatible with a range of non-ferrous metals.

  Because of the high startup costs associated with die casting, the process is typically used for high-volume production, where the scale of manufacturing makes up for the high machinery and tooling costs. Die cast prototypes and low-volume production runs are harder to obtain, as it is in the economic interests of die casting companies to work with customers placing bulk orders. However, 3ERP currently provides a unique die casting solution for customers wishing to place smaller die casting orders.

  This article takes an in-depth look at metal die casting, explaining the suitable materials, surface finishes, and applications for the process.

   

  What is die casting?

  Die casting is a type of metal casting that uses high pressure to force molten metal into a mold cavity formed by two dies. It shares traits with the plastic manufacturing process of injection molding.

  Within the larger metal casting landscape, die casting is one of the most popular techniques due to its accuracy, high quality, and level of detail. The broader category of metal casting, which has existed for thousands of years, contains many different processes that use a mold to form liquid metal. Historically, such a process usually involved pouring the liquid metal into the mold with the aid of gravity &#; and many metal casting processes still work this way. Die casting, however, is a relatively new form of metal casting, introduced in the 19th century, and it uses pressure instead of gravity to fill the mold cavity.

  Die casting is sometimes called high-pressure die casting, due to the amount of pressure &#; typically 10&#;140 megapascals &#; used to force the metal into the mold cavity. The related process of low-pressure die casting (LPDC) is less common. Die casting typically falls into one of two categories: hot-chamber die casting and cold-chamber die casting, which are suitable for different types of metal. However, there are also other more niche types of die casting, such as semi-solid metal casting (SSM).

   

  Cast Aluminum: Everything You Need to Know

  Cast aluminum is a specific aluminum that is formed by casting technique. There is a wide application of cast aluminum due to its lightweight yet good strength. Cast aluminum could be seen in both daily life and industrial applications, such as cast aluminum cookware, cast aluminum chair legs, cast aluminum pumps, and more.

  As a professional casting company, we can produce custom cast aluminum parts following your drawing&#;s specifications. There are several aluminum casting processes available at our foundry, including aluminum die casting, aluminum gravity casting and aluminum sand casting. Each casting process has its special advantages, and we can recommend a best suitable casting process according to the design of the aluminum part.

  What is Cast Aluminum?

   

  Cast aluminum refers to aluminum that has been heated to its melting point before pouring it into molds for specific shapes or forms. The casting process involves heating aluminum until its melting point has been reached, then pouring it in an appropriate mold where it cools and solidifies to produce desired forms or shapes. After casting, post operations such as trimming and surface grinding are performed to achieve net shape castings.

  Benefits of Cast Aluminum

  Cast aluminum, particularly from manufacturers, offers a range of benefits for various applications. Here&#;s a closer look at the advantages of cast aluminum:

  Complex Design Capability

  Cast aluminum has its ability to creat parts into complex shapes, no matter how intricate the design is. For its excellent fluidity of aluminum alloys, thet can fill mold cavities completely, and an exact solid cast piece is formed after solidification. 

  Lightweight Yet Strong

  Aluminum is known for its high strength-to-weight ratio. Parts made from cast aluminum can provide the required strength for great working performace, while maintaning light weig

  ht part. This is not available when parts made from other casting materials such as cast steel or cast iron. This benefit makes cast aluminum a good application especially for automotive and aerospace industries.

  Excellent Corrosion Resistance

  When exposed to atmospheric conditions, aluminum can naturally form an oxide layer, this protects it against corrosion. So, after casting, cast aluminum parts have excellent corrosion resistance, which make them an ideal choice in harsh or corrosive environments, like marine applications or outdoor furniture. If there is a higher requirement, cast aluminum parts could be further anodized or powder painted to improve its enchace its corrosion resistance capacity.

  Faster Speed of Production

  The casting process of aluminum parts is always faster than other manufacturing process, such as machining or welding fabrication process. As most of the aluminum casting processes are automated, once the molds are prepared, the production process of cast aluminum parts is very fast. Cast aluminum can provide shorter lead times while high quality products.

  Cost-effectiveness for Manufacturing

  Even with an intial investment in mold, due to the great production speed and less material waste, the cost per cast aluminum part is very economical. Besides, cast aluminum has the ability to creat a simple piece in complex shapes, and reduce or remove the need for post machining, which lower the production cost in further step.

  The Casting Processes for Aluminum

   

  1. Low / High Pressure Die Casting

  Low Pressure Die Casting (LPDC) is the casting process that can produce cast aluminum parts at low pressure, typically between 20 psi and 100 psi. In this process, aluminum is melted and then tranferred into a mold under low pressure until the aluminum solidifies. Cast aluminum parts made from this process can achieve good dimensional accuracy even in medium to high volumes. It is particularly suitable for making cast aluminum parts in thicker wall thickness.

  High Pressure Die Casting (HPDC), as its name implies, creats cast caluminum parts at high pressure, typically between 10,000 and 15,000 psi. In this process, molten aluminum is injected into a mold under high pressure fastly. By high pressure die casting, thin-walled cast aluminum parts with complex shapes could be made. Besides, it also allows for high volume production. The strength of cast aluminum made in this process is the best among all the aluminum casting processes.

  2. Gravity Die Casting

  Gravity Die Casting, sometimes referred to as permanent mold casting, involves pouring molten aluminum into metal molds using gravity for permanent cast aluminum production. Molds made of steel or cast iron typically can support useable multiple cycles, which make gravity die casting an economical medium-to-high volume production method. Cast aluminum parts made from this process can achieve improved mechanical properties and finer surface finishes than sand casting method.

  3. Sand Casting

  As one of the most versatile casting processes available today, sand casting is not limited to make cast steel and cast iron parts, it can creat cast aluminum parts as well. Cast aluminum parts with intricate geometries are usually made in sand casting process, which is challenging by other casting methods. Aluminum sand casting process involves creating a mold from sand mixture, then pouring molten aluminum into it for solification. Next, the mold is broken away to take out the finished cast aluminum part. This process prpvides flexibility on mold design, so it supports both small and large cast aluminum parts with intricate shapes. While the surface is rougher when compared with die casting process.

  Common Cast Aluminum Alloys

   

  Because of the excellent mechanical properties and casting ability, cast aluminum is widely used by many industries. At Foundry, we have the capability to produce cast aluminum parts in different alloys, including A356, A360, A380, A383. They have unique chemical compositions, each alloy shows district advantages for different applications.

  A356 Aluminum Alloy

  A356 aluminum alloy is the most common material in aluminum gravity casting. The T6 heat treatment can further improve its strength and will be helpful for machining operation. The main chemical elements of A356 alloy include aluminum, magnesium (0.02-0.45%), silicon (6.5-7.5%) and other elements. Due to its good castability, welding ability and corrosion resistance, it is widely used in aluminum gravity casting process to creat parts with high strength and ductility. A356 castings are widely used in automotive and aerospace applications, as well as other industries.

  A360 Aluminum Alloy

  The A360 aluminum alloy mainlt consists of elements like aluminum, magnesium (0.4-0.6%), silicon (9-10%) and copper (6%). These compositions increases its strength and corrosion resistance when compared to other metals. A360 can offer good pressure tightness, which is critical for fluid-handling components. The excellent castability of A360 and its aesthetic surface finish makes it a good choice for casting housings, connectors and complex automotive components.

  A380 Aluminum Alloy

  A380 is a widely used cast aluminum alloy that contains aluminum, silicon (7.5-9.5%), copper (3-4%) and other elements such as iron, nickel and zinc. It is a versatile die casting material due to its high thermal conductivity and fluidity.

  A383 Aluminum Alloy (ADC12)

  A383, also known as ADC12, is also a common die cast aluminum alloy. Its composition differences can improve its casting characteristics when compared with A380 alloy. This alloy includes elements like copper, silicon, and aluminum (9.5-11.5%).

  How To Select a Right Casting Process for Aluminum?

  When selecting a right casting process for aluminum parts, it is necessary to evaluate both the usage of the part and the material properties of cast aluminum alloy. 

  Design Complexity

  The complexity and detail of any design play an essential part in selecting an optimal casting process. High-pressure die casting specialises in producing parts with intricate geometries and tight tolerances, making it ideal for creating aluminum parts with fine details and high accuracy. So, when the cast aluminum parts have a high requirement on dimensional accuracy and surface finish, high pressure die casting is the best choice for high volume production. For simpler or thicker designed parts, gravity die casting or sand casting may offer more cost effective solutions. Besides, sand casting is also suitable for large cast aluminum parts in small volume production.

  Production Volume

  Production volumes is also a necessary consideration factor for cast aluminum parts production. For high-pressure die casting, it is only cost effective for high volume production runs due to its high investment on the mold cost. Of course, it is worth to mention that the production efficiency is also very high. Medium volume projects might consider gravity die casting. While for low and prototype runs, sand casting may offer advantages due to reduced tooling costs, although its per-unit costs are higher.

  Material Properties and Performance

  For its superior strength-to-weight ratio and corrosion resistance of aluminum alloys, they are widely used in casting production. Casting process will further affect the properties. For example, high pressure die casting creates denser microstructures which enhance mechanical properties but increase porosity. Gravity die casting provides excellent material integrity which makes this approach ideal for moderate strength applications. While sand casting produces coarser microstructures which may result in parts with lower mechanical properties than expected &#; it is therefore vital that we clearly establish any performance expectations before choosing this form of casting as our final solution!

  Surface Finish

  The surface finish is also an important factor to consider when selecting an aluminum casting process. High pressure die casting can provide the finest surface quality of cast aluminum parts, and less or no machining is needed after casting. Low pressure die casting sand gravity die casting also offer good surface finish after fine blasting. While sand casting often provides rougher surface finish, which usually need further machining to achieve higher surface finish.

  Cost Considerations

  Cost factor could not be ignored when selecting a casting process for aluminum parts. High pressure die casting has the advantages of speed, precision and surface finish, but it requires a high tooling investment, and is more ideal for large orders. Gravity die casing and low pressure die casting offer lower tooling cost, but its unit cost is relatively higher. Sand casting is a most econimical selection for low volume production, while its unit cost per part is the highest when compared with other casting processes, and additional machining operation is usually required for closer tolerances or higher surface finish.

  Cast Aluminum vs. Forged Aluminum

  The fundamental difference between Cast and forged aluminum is easy to understand: Cast aluminum is the aluminum that was melted in a furnace and poured into a mold. Forged aluminum is when the metal is worked in the solid form with the help of specific tools. These two manufacturing processes will yield two materials with very different properties.

  Aluminum has a wide range of uses across every major industry, however, it is often difficult to decide which grade is best suited to a specific application. The challenge becomes greater when comparing not only between alloys but also between cast and forged aluminum. Both are fundamentally aluminum alloys which often have the same alloying elements but in different compositions and quantities. However, the applications and material properties vary widely between the two.

  Examples of Cast Aluminum Products

   

  You may be surprised to find out that many of the commercial products you come in contact with every day may be using cast aluminum parts and components or even be made entirely from cast aluminum.

  Car Parts

  Due to the amazing strength and light weight of cast aluminum parts, it is very popular in the production of car parts. For example, safety-critical parts like airbag housings or seat-belt retractor spools are made with diecast aluminum. In addition, steering knuckles, which support the wheel bearing, are made with this material. This is an essential part of a vehicle&#;s suspension, so the lightweight material helps to reduce the overall weight of the car without compromising strength or performance.

  Lighting Parts

  Due to the light weight and good corrosion resistance of cast aluminum, it is always used as the casting alloy for various lighting parts. Cast aluminum lighting parts could be designed and produced by either gravity die casting or high pressure die casting process.

  Medical Devices

  Many medical devices are also made from cast aluminum, not only due to the strength but also due to its heat resistance. Some of the more common medical equipment you may see made from this metal is parts for various pumps, surgical tools, components for monitors, and even gearboxes for hospital beds.

  Firearms

  Another popular application for die casting is the production of firearms. While many popular firearms may have plastic components, there are still a number of parts that are created from die-cast metals. Some of these parts may include triggers, trigger guards, trigger safetys, and much more.

  Cast Aluminum Cookware

  For decades, cast aluminum cookware (flater beater, dough hook, etc)  has been a vital tool in a well-stocked home kitchen. The versatile product is perfectly suited for cooking on the stovetop and baking in the over. It is dishwasher safe, making for a quick and easy clean up. Despite some ridiculous reports, it is safe to use for cooking and poses no health risks at all.

  If you&#;re looking for pots and pans made from this material, the good news is they&#;re everywhere. You can find brand-new sets on the websites of major retailers. If a more classic style is what you are after, you can even find vintage cast cookware on eBay.

  Cast Aluminum Patio Furniture

  When you think about investing in patio furniture you want something attractive, durable, and low-maintenance. If you also want an outdoor ensemble that&#;s available in a variety of styles, finishes, and colors, cast aluminum patio furniture including cast aluminum chair legs may provide you with an ideal setting to enjoy entertaining and relaxing with family and friends.

   

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• Maximum relative density was reported for XY printed samples (97.33 ± 0.92%). However, maximum hardness was reported for the 45° orientation printed samples (47.32 ± 3.35 HV).

SLM Solution M280 GmbH[92]Ngnekou et al. ()AlSi10MgLaser powers 200 W and 400 W.
Build Orientation: XY and Z
Heat treatment: Stress relieved at 160 °C for 1 h or 300 °C for 2 h, T6 heat treatment involving solution treated at 540 °C for 8 h, water quenched, and tempered at either 20 °C for 24 h or 160 °C for 10 h.Fatigue

• The improvement in fatigue resistance is less pronounced when large-sized defects are present in the printed samples.

• There is no influence of the defect type on the fatigue limit.

Phenix PM100 3D Systems machine
EOS M290 machine [93]Nurel et al. ()AlSi10MgLaser power 400 W, spot diameter 80 µm, scan velocity mm/s, strip scanning strategy, hatch distance 200 µm, hatch rotation 67°, layer thickness 60 µm, argon atmosphere, build plate temperature 35 °C.
Build orientation: Horizontal and Vertical
Heat Treatment: T5/Stress relief treated at 300 °C for 2 h.Dynamic-Compression

• The dynamic anisotropic properties were insensitive to variation in strain rates.

• Anisotropic differences were considerably reduced by applying T5 heat treatment.

• The as-built samples failed after SHPB tests which was observed in the T5 heat treated samples.

EOSINT M280 system[94]Nurel et al. ()AlSi10MgLaser power 400 W, spot diameter 80 µm, layer thickness 30 µm.
Build orientation: Horizontal and Vertical.
Heat treatment: T5 at 300 °C for 2 h.Dynamic-Compression

• No strain sensitivity was observed.

• True stress for as-built and heat-treated conditions are 569 ± 8.5 MPa and 427 ± 4.8 MPa respectively.

EOSINT M280 system[95]Ojha et al. ()AlSi10MgLaser power 100 W, scanning speed mm/s, spot size 0.2 mm, layer thickness 80 µm.Modelling and simulation

• FEA was carried out to investigate temperature evolution, heat transfer and solidification process.

• Simulation results are dependent on process parameters along with material properties.

-[96]Pei et al. ()AlSi10MgLaser power 180 W, scanning speed 600&#; mm/s, layer thickness 35 µm, spot size 70 µm.Modelling and simulation

• The perturbation or the instability within the molten pool results in the formation of pores during SLM, which have a direct influence on the densification level.

• At high scanning speed, the track morphology became discontinuous leading to poor bonding and balling.

SLM-150 equipment[97]Pola et al. ()AlSi10Mg-Fatigue, porosity, surface roughness, tensile

• Post-treatment is effective in reducing surface roughness and inducing compressive residual stresses on the material surface.

• Sand blasting had a beneficial effect of the fatigue resistance.

EOS M290 system[98]Ponnusamy et al. ()AlSi12Laser power 285 W, scanning speed mm/s, hatch spacing 100 µm, layer thickness 40 µm, defocus distance &#;4 mm, alternative scan strategy.
Build orientation: Horizontal, Inclined, VerticalDynamic - Compression

• The dynamic compressive strength increased with an increase in the angle of print orientation, i.e., from 0° to 90°.

• The yield strength and compressive strength decrease for printed samples tested at elevated temperature of 200 °C.

• The flow stress was found to be higher for dynamic loading compared to quasi-static loading at elevated temperature.

3D Systems ProX 200[99]Ponnusamy et al. ()AlSi12Laser power 285 W, scanning speed mm/s, hatch spacing 100 µm, layer thickness 40 µm, defocus distance &#;4 mm, alternative scan strategy, hexagon scan pattern, argon atmosphere.
Build orientation: Vertical
Heat treatment: Annealed at 200 °C and 400 °C for 3 hrs.Dynamic compression

• Thermal softening was observed in printed samples tested at elevated temperatures, which resulted in significant reduction in flow stress.

• A 20% and 50% reduction in flow stress was observed when samples were tested at 200 °C and 400 °C test temperatures, respectively.

• A 12% and 45% reduction in flow stress was observed for samples heat treated at 200 °C and 400 °C, respectively, and then tested.

ProX 200[100]Prashanth et al. ()AlSi12Laser power 320 W, layer thickness 50 µm, hatch spacing 110 µm, hatch rotation 73°, scanning speed &#; mm/s, argon atmosphere.
Build orientation: 30°, 45°, 60°, 75°, 90°.
Heat treatment: Solution treated at 473&#;723 K for 6 h.Wear rate, corrosion properties

• As-built samples exhibit better wear resistance and similar corrosion resistance compared to cast counterparts.

• Both wear and corrosion properties deteriorated with annealing post heat treatment, due to growth of Si precipitates.

SLM 250 HL[16]Prashanth et al. ()AlSi12Laser power 320 W, layer thickness 50 µm, hatch spacing 110 µm, hatch rotation 73°, scanning speed &#; mm/s, argon atmosphere, scan strategies included single melt, double melt, single melt continuous, and checkerboard, base plate heating 473&#;673 K.
Heat treatment: Solution treated at 473&#;723 K for 6 h.Tensile

• The difference in tensile properties were attributed to the variation in crack propagation path.

• The samples printed without contour exhibited significant increase in ductility without compromising on the tensile strength.

• The results indicate that the room temperature tensile properties can be tuned (between YS: 115&#;290 MPa, UTS: 220&#;460 MPa and ductility: 2.8&#;9.5%) in-situ with appropriate selection of process parameters.

SLM 250 HL[101]Prashanth et al. ()AlSi12Laser power 320 W, layer thickness 50 µm, hatch spacing 110 µm, hatch rotation 73°, scanning speed &#; mm/s, argon atmosphere.
Build orientation: 30°, 45°, 60°, 75°, 90°.
Heat treatment: Solution treated at 473&#;723 K for 6 h.Tensile

• The Al and Si phases show remarkably small crystallite sizes of about 118 and 8 nm.

• The as-built samples exhibited a yield strength of 260 MPa and tensile strength of 380 MPa, which was significantly higher than the cast counterparts.

• The texture of the microstructure of the printed samples varied with variation in build orientations, however, this did not affect the tensile properties.

SLM 250 HL[17]Qiu et al. ()AlSi10MgLaser power 150&#;400 W, beam spot size 50 µm, scanning speed &#; mm/s. Compression

• The dimensions of the melt pool increased with an increase in laser power resulting in strut diameters deviating from the designed values.

• The compressive load bearing capacity of the lattice structures increased with an increase in strut diameter.

• Deformation of lattice structures occurred by homogeneous deformation until the maximum stress was achieved after which the structure lost structural integrity via a series of shear banding events at around 45° to the compression axis.

Concept Laser M2 Cusing SLM system[102]Rakesh et al. ()AlSi10MgLaser beam diameter 80 µm, argon/nitrogen gas inert atmosphere.
Build orientation: Transverse (XZ), Longitudinal (Y)Tensile, Impact strength

• Printed samples displayed superior tensile strength (~350 MPa) and impact strength compared to cast parts.

• Significant improvements in tensile properties and impact energies were observed in the transversely-built samples irrespective of the chamber atmosphere.

EOSINT M280 machine[103]Rao et al. ()A357Laser power 100&#;370 W, layer thickness 30 µm, hatch distance 0.1 mm, spot size diameter 0.1 mm, scan speed 500&#; mm/s, substrate temperature 35&#;200 °C.
Build orientation: Horizontal, Vertical.Tensile

• The mechanical property was largely affected by different substrate temperatures.

• The coarse Si precipitates formed along the build direction facilitates intercellular failure, resulting in poor tensile properties.

EOSINT M280[25]Rao et al. ()A357Laser power 100&#;370 W, layer thickness 30 µm, hatch distance 0.1 mm, spot size diameter 0.1 mm, scan speed 500&#; mm/s, substrate temperature 35&#;200 °C.
Heat treatment: Stress relieving at 300 ± 1 °C and air-cooled, solution treating at 535 ± 3 °C in salt bath from 0.25 h to 150 h followed by water quenching.Tensile

• The as-built samples had an ultrafine microstructure, with high residual stresses and non-equilibrium solid solute concentration of Si in the supersaturated Al matrix.

• The tensile properties of the printed A357 samples were comparable or better than the traditional cast counterparts.

• The UTS and YS of as-built sample are 426.4 ± 2.6 MPa and 279.6 ± 1, respectively, however, the ductility was found to improve after stress-relieving (13.6 ± 0.6%).

EOSINT M280[24]Rashid et al. ()AlSi12Laser power 285 W, scan speed &#; mm/s, layer thickness 40 µm, hatch distance 100 µm, defocus distance &#;4 mm.
Build orientation: Horizontal, Inclined (45°), VerticalTensile, density

• Energy per layer in the range of 504&#;895 J yielded &#; 99.8% relatively dense AlSi12 SLM-printed samples.

• Yield strength range 225&#;263 MPa, tensile strength range 260&#;365 MPa, and ductility range 1&#;4% was found for the printed samples with different build orientations.

• Anisotropy in mechanical properties was attributed to differences in relative densities.

ProX 200[104]Rashid et al. ()AlSi12Laser power 285 W, scan speed &#; mm/s, layer thickness 40 µm, hatch distance 100 µm, defocus distance &#;4 mm.
Lattice structures: Circular cells, honeycomb cells, triangular cellsFlexural

• The printed samples exhibited brittle failure.

• Triangular lattice structure had the highest flexural strength of 175.80 ± 1 MPa, circular 151.35 ± 0.67 MPa, and honeycomb 143.16 ± 3.85 MPa, whereas the solid specimen had a strength of 290 ± 26 MPa.

• Triangular lattice structure showed good flexural modulus of 5 GPa compared to the honeycomb structure (4.34 GPa) and circular structure (4.37 GPa).

ProX 200[105]Rathod et al. ()AlSi12Laser power 320 W, scan speed mm/s, layer thickness 50 µm, and hatch spacing 110 µm.Wear

• Printed samples displayed significant anisotropy in wear rate due to change in laser track orientation.

• Porosity significantly affected the wear rate.

280HL equipment [106]Raus et al. ()AlSi10MgLaser spot size 80 µm, laser power 350 W, scan speed mm/s, layer thickness 30 µm, hatch distance 0.13 mm, stripe scanning strategy, argon atmosphere, build platform temperature 150 °C.Tensile, hardness, impact toughness

• Porosities of the order of 5 to 20 µm were observed in relatively dense (99.13%) sample.

• Printed samples displayed higher mechanical properties compared to high pressure die cast samples.

SLM 125 HL[107]Read et al. ()AlSi10MgLaser power 100&#;200 W, laser track width 150 µm, layer thickness 30 µm, scan speed 700&#; mm/s, hatch spacing 0.2&#;0.8 mm, island scanning strategy, island size 2&#;8 mm, argon atmosphere.
Build orientation: Horizontal, Vertical.Tensile, creep resistance

• A critical energy density of 60 J/mm3 was found wherein minimum pore fraction was observed.

• Creep results showed better rupture life than cast alloy, displaying good agreement with the Larson&#;Miller literature data.

• Unmelted powder particles give rise to local cracking, as observed on the fracture surfaces.

Concept Laser M2 Cusing SLM system[108]Rosenthal et al. ()AlSi10MgLaser power 400 W, laser spot size 100 µm, scan velocity mm/s, strip scanning strategy, hatch rotation 67°.Tensile, density

• The mechanical properties of the printed parts displayed a strong dependency on the microstructure and are comparable or higher than cast part after T6 heat treatment.

EOSINT M280[109]Rosenthal et al. ()AlSi10MgLaser power 400 W, laser spot size 100 µm, scan velocity mm/s, hatch distance 200 µm, layer thickness 60 µm, argon atmosphere.
Build orientation: Horizontal (X), Vertical (Z).
Heat Treatment: T5 stress relief treatment at 300 °C for 2 h, modified T5 at 200 °C for 2 h.Impact resistance

• Horizontally built specimens absorbed more impact energy compared to vertically built specimens.

EOSINT M280[110]Rosenthal and Stern ()AlSi10MgLaser power 400 W, laser spot size 100 µm, scan velocity mm/s, hatch distance 200 µm, layer thickness 60 µm.
Heat treatment: Treated at 100&#;250 °C for 2 h, treated at 200 °C for 168 h, treated at 100 °C for 336 h.Hardness

• Results revealed that the heat treatments conducted in the range of 100 °C&#;300 °C displayed noticeable increase in hardness values due to precipitation/coarsening of the Si phase.

EOSINT M280[111]Rosenthal et al. ()AlSi10MgLaser power 400 W, scanning speed mm/s, strip scanning strategy
Build orientation: Vertical, Horizontal.
Heat treatment: Stress relieving at 300 °C for 2 h.Tensile, hardness, fracture morphology

• The printed parts displayed room temperature mechanical properties comparable or even exceeding conventionally cast AlSi10Mg samples.

• In the vertical orientation, the samples display Young&#;s modulus of 69.5 to 73 GPa, yield strength 167&#;170 MPa, UTS 269&#;277 MPa and elongation ranging 7.8&#;8.7%, whereas in the horizontal orientation Young&#;s Modulus ranges between 69&#;71.3 GPa, yield strength 168&#;170 MPa, UTS of 267 MPa and elongation ranging 8.6&#;9.5%.

-[112]Rosenthal et al. ()AlSi10MgLaser power 400 W, laser spot size 100 µm, scan velocity mm/s, hatch distance 200 µm, layer thickness 60 µm, argon atmosphere, build plate temperature 35 °C, strip scanning strategy, hatch rotation 67°.
Build orientation: Vertical, Horizontal.Tensile, fracture surface analysis

• Printed samples were sensitive to strain rate variations with significant changes to the flow stress and strain hardening exponents with an increase in strain rate.

• The strain rate sensitivity was similar in both vertical and horizontally printed samples, while the true strain was significantly higher in the samples built in the horizontal orientation.

EOSINT M280[113]Samantaray et al. ()AlSi10MgLaser power ranging 70&#;190 W, laser spot diameter 0.2 mm, scanning speed 100&#;500 mm/s, layer thickness 1 mm.Modelling and simulation

• The maximum temperature of the molten pool increased from 731 °C to °C and the molten pool length changed from 0.286 mm to 2.167 mm, when the laser power increased from 70 W to 190 W.

• The sintering depth of the powder layer increased with an increase in laser power but decreased when the scan speed was increased.

-[114]Siddique et al. ()AlSi12Laser power 400 W, volume energy density 39.6 J/mm3, argon atmosphere.
Heat treatment: Stress relieving at 240 °C for 2 h followed by oven cooling.Fatigue, tensile

• The microstructure of the printed samples consisted of fine grains and precipitates that resulted in increased quasi-static strength compared to that of the cast counterparts.

• The fatigue strength of the as-built hybrid samples was comparably better than the as-built samples.

SLM 250[115]Siddique et al. ()AlSi12Laser power 350 W, scan speed 930 mm/s, hatch distance 0.19&#;0.25 mm, energy density 20&#;39.6 J/mm3, argon atmosphere.
Heat treatment: Stress relieving at 200 °C followed by oven cooling.Fatigue, porosity, modelling and simulation

• Similar porosity percentage was found using optical microscopy and X-ray computed tomography techniques.

• Hot isostatic pressing post treatment resulted in reduction of strength, however, was comparable to that of the die-cast parts.

• Even smaller size pores present in the vicinity of the surface of the fatigue samples, significantly contributed to the decrease in fatigue life. This surface weakness effect was mitigated by the hot isostatic pressing post treatment.

SLM 250 HL[116]Siddique et al. ()AlSi12Laser power 350 W, scan speed 930 mm/s, hatch spacing 0.19 mm, layer thickness 50 µm, energy density 39.6 J/mm3, scanning strategy chessboard, hatch rotation 79°, argon atmosphere, base plate temperature 200 °C.
Build orientation: Vertical.
Heat treatment: Stress relieving at 200 °C for 2 h.Fatigue, porosity, hardness, crack propagation testing

• Stress relief post heat treatment at 240 °C caused an increase in porosity due to the growth of pores.

• At low stresses, the samples printed with base plate heating displayed higher fatigue performance compared to the samples printed without base plate heating.

• Samples printed without base plate heating consisted of higher porosity, which facilitated samples failing from cracking due to defects. Such an occurrence was significantly reduced in samples printed with base plate heating.

SLM 250 HL[14]Siddique et al. ()AlSi12Laser power of 400 W, energy density 20&#;39.6 J/mm3, chessboard scanning strategy, hatch rotation 79°, argon atmosphere, base plate temperature 200 °C.
Build orientation: Vertical.
Heat treatment: Stress relieving at 240 °C followed by oven cooling.Tensile, surface roughness, residual stress analysis, fatigue

• Base plate heating induces a coarser grain microstructure in the printed samples owing to a decrease in cooling rate.

• Tensile strength of the printed samples was four times that of sand-cast parts and two times that of die-cast parts.

• Significant reduction in residual stresses was observed in samples printed with base plate heating, which also reduced the scatter in fatigue data.

SLM 250 HL[15]Silvestri et al. ()AlSi10MgEOS M400: Laser power W, laser spot diameter 90 µm, nitrogen atmosphere.
SLM 280: Laser power 400&#; W, laser spot diameter 80&#;225 µm, argon atmosphere.
Renishaw AM400: Laser power 400 W, laser spot diameter 70 µm, argon atmosphere.
Build orientation: 0°, 60°, 90°.Tensile

• The mechanical properties of the samples printed using different SLM machines were different, even though the best process parameters suggested by the equipment manufacturers were employed.

EOS M400
SLM 280
Renishaw AM400[117]Subbiah et al. ()AlSi10MgLaser power 350 W, laser spot size 0.2 mm, scanning speed 730 mm/s, hatch spacing 0.12 mm, layer thickness 30 µm, stripe scanning strategy, inert atmosphere, base plate temperature 150 °C.
Heat treatment: Solution treated at 550 °C for 2 h and water quenched.Tensile, surface roughness, modelling and simulation

• The microstructural studies revealed that the samples were stretched due to the exclusion of Si enriched cellular and dendritic network.

• Printed samples exhibited high tensile strength of 431 MPa.

SLM 280 HL[118]Sun et al. ()AlSi10MgLaser power 400 W, laser spot size 100 µm, scanning speed mm/s, hatch spacing 0.165 mm, layer thickness 25 µm, chessboard scanning strategy, hatch rotation 67°.
Heat Treatment: T2 treatment&#;annealed at 380 °C for 45 mins and air cooled, T6-like treatment&#;solution treated at 500 °C for 15 mins, quenched, and aged at 158 °C for 10 mins.Tensile

• A homogeneous distribution of spheroidised Si was observed in heat treated parts.

• It was suspected that Si experienced the necking effect under a tensile environment due to the large temperature gradient and α-Al erosion during the SLM process.

• The tensile strength of the as-built samples was better than the as-cast samples, however, the strength reduced with subsequent post heat treatment.

Renishaw AM 250[119]Suryawanshi et al. ()AlSi12Laser power 320 W, layer thickness 50 µm, hatch spacing 110 µm, hatch rotation 73°, scanning speed ( mm/s for volume and mm/s for contour), argon atmosphere, single melt and checkerboard scanning strategy.
Heat treatment: solution treated at 573 K for 6 h.Tensile, fracture toughness, fatigue crack growth

• The fatigue crack growth threshold and unnotched fatigue strength of SLM alloys was inferior compared to cast alloys, which could be attributed to tensile residual stresses, shrinkage porosity, and un-melted particles.

• The printed samples exhibited enhanced toughness due to the presence of mesostructure Si.

• Toughness was found to be sensitive to crack orientation with respect to the build and scan orientations.

SLM 250 HL[120]Takata et al. ()AlSi10MgLaser power 380 W, layer thickness 30 µm, hatch spacing 0.1 mm, hatch rotation 67°, argon atmosphere.
Build orientation: Horizontal (X/Y), Vertical (Z).
Heat treatment: Annealing at 300 °C for 2 h, or solution treatment at 530 °C for 6 h and water quenched.Tensile

• A fine dislocation substructure consisting of low angle boundaries was found within the α-Al grains.

• {001} texture along the Z direction was observed which was attributed to the preferential <001> grain growth of the α-Al phase during rapid solidification.

• The as-built samples exhibited a high tensile strength of approximately 480 MPa irrespective of the build orientation. In contrast, the ductility was direction-dependent, thereby resulting in the fracture preferentially occurring at the melt pool boundaries.

EOSINT M 280[121]Tang and Pistorius ()AlSi10MgLaser power 370 W, scan speed mm/s, layer thickness 30 µm, laser spot diameter 100 µm, hatch spacing 0.16&#;0.22 mm, hatch rotation 67°.
Build orientation: XY, Z.
Heat treatment: Stress relieving at 573 K for 2 h.Tensile, fracture morphology, porosity

• The Z-oriented samples flow at a lower imposed stress than the XY-oriented samples.

• The maximum yield strength was noted for the XY-built samples, while maximum tensile strength was observed for the Z-built samples.

• Variation in hatch spacing results in porosity formation in the printed parts, which subsequently reduced the tensile performance.

EOS M280[122]Tang and Pistorius ()AlSi10MgLaser power 370 W, scan speed mm/s, laser beam diameter 0.1 mm, layer thickness 30 µm, hatch spacing 0.16&#;0.22 mm, and the
Build orientation: XY, Z.
Heat treatment: Stress relieving at 573 K for 2 h.Fatigue, porosity

• A correlation between the crack-initiating pore on the fracture surface and fatigue life was established.

• The fatigue resistance was affected by the variation in hatch spacing and build orientation.

• XY-oriented samples have better fatigue performance, possibly due to anisotropy of pores, residual stress, and of melt-pool boundaries.

EOS M280[123]Tradowsky et al. ()AlSi10MgLaser power 175 W, laser spot size 60 µm, scan speed mm/s, layer thickness 30 µm, scan spacing 97.5 µm, chess scanning strategy, island size 5.6 mm, argon atmosphere.
Build orientation: Horizontal, Vertical.
Heat treatment: Solution treated at 520 °C for 5 h, water quenched, and aged at 160 °C for 12 h followed by air cooling.Tensile, porosity, modelling and simulation

• Columnar grains were observed along building direction, with equiaxed grains found in-cross section.

• Irregular-shaped voids were observed in both the as-built and heat-treated conditions due to the formation of oxide layer. These pores were considerably reduced after hot isostatic pressing post treatment, however, the oxide layers remained.

• Heat treated and hot isostatic pressed samples had tensile properties exceeding that of the cast counterparts.

Concept Laser M2 cusing system[124]Trevisan et al. ()A357Laser power 195 W, spot size 100 µm, layer thickness 30 µm, scanning speed mm/s, hatch distance 0.1 mm, hatch rotation 67°, build plate temperature 100 °C.
Heat treatment: Stress relieving at 300 °C for 2 h, T6 treatment involving solution treatment at 540 °C for 8 h, water quench, and ageing at 170 °C for 3 h.Tensile, hardness

• The tensile strength decreased after stress relief heat treatment.

• After T6 heat treatment, the microstructure became more isotropic, and the mechanical properties were comparable to that of the as-built condition.

EOSINT M270 Dual mode machine[125]Uzan et al. ()AlSi10MgLaser power 400 W, beam diameter 100&#;150 µm, scanning speed mm/s, layer thickness 30 µm and 60 µm (before and after melting), hatch distance 200 µm, stripe scanning strategy, argon atmosphere, build plate temperature 35 °C.
Build orientation: Z direction.
Heat treatment: Stress relieved at 300 °C for 2 h.Fatigue, tensile, fracture toughness, hardness

• The fatigue resistance of the as-built samples was highest and that of the stress relieved and hot isostatic pressed samples was the lowest.

• The critical stress intensity factor can be estimated by the fracture surface morphology of the fatigue specimen.

EOSINT M-280 [126]Vrana et al. ()AlSi10MgLaser power 150&#;400 W, layer thickness 50 µm, scanning speed &#; mm/s, nitrogen atmosphere, build platform temperature 120 °C.Impact testing

• Lattice structures fabricated with scanning speed of 500 mm/s achieved 10× higher stiffness than those printed using mm/s for the same geometry of the unit-cell.

• Samples printed with a laser power of 350 W and scanning speed of mm/s achieve greater geometrical stability and had better accuracy.

SLM 280HL[127]Wang et al. ()AlSi10MgLaser power 370 W, scan speed mm/s, hatch spacing 190 µm, layer thickness 30 µm, argon atmosphere.
Build orientation: Vertical.
Heat treatment: Stress relieved at 250 °C for 4 h.Tensile, porosity, modelling and simulation

• The deviation between reconstructed and as-designed models was less than 100 μm.

• The anisotropic properties of the printed parts were attributed to the non-uniform distribution of process-induced defects within the samples, which had a deleterious effect on the tensile strength.

• The presence of geometric defects significantly influenced the tensile strength and elongation.

EOS M290[128]Wang et al. ()AlSi10MgLaser power 400 W, laser spot size 76 µm, scanning speed mm/s, hatch distance 175 µm, layer thickness 25 µm, chessboard scanning strategy, island size 5 mm, argon atmosphere.
Heat treatment: T6 solution treated at 535 °C for 7&#;15 mins and aged at 158 °C for 10 h.Tensile, bending, hardness

• A decrease of about 20% in hardness and tensile strength whereas an increase of about 155% in elongation was reported for the heat-treated samples.

• An increase of about 123% in fracture deflection and a decrease of about 6% in bending strength was also found for the heat-treated samples.

Renishaw AM 250[129]Wang et al. ()AlSi10MgLaser power 400 W, scanning speed mm/s, hatch spacing 175 µm, layer thickness 25 µm, chessboard scanning strategy, hatch rotation 67°.
Build orientation: Parallel, Normal.
Heat Treatment: T2 stress relieving treatment at 380 °C for 45 mins followed by air cooling.Tensile, bending, hardness

• The hardness, tensile strength and bending strength decrease by about 50% after T2 heat treatment

• The precipitates in the molten pool boundaries dissolve in the matrix after heat treatment.

Renishaw AM 250 system[130]Wang et al. ()AlSi12Laser power 200 W, beam diameter 35 µm, scanning speed 375&#; mm/s, hatch spacing 0.15 mm, layer thickness 50 µm, stripe scanning strategy, hatch rotation 90°, inert atmosphere.Tensile, hardness

• Insignificant differences in density and hardness was observed when the samples were printed in either argon, nitrogen, or helium chamber atmospheres.

• The samples showed superior performance; 1.5 times yield strength, 20% higher tensile strength, and twice elongation, compared to conventionally produced material.

Realizer SLM 100[131]Wei et al. ()AlSi10MgLaser spot size 70 µm, laser power 150&#;180 W, scanning speed 600&#; mm/s, layer thickness 40 µm, hatch spacing 50&#;70 µm, random scanning strategy, argon atmosphere.Tensile, fracture morphology

• A linear energy density of 1.5&#;1.875 J/cm was reported to yield continuous single-track depositions.

• The level of porosity was significantly influenced by the variation in hatch spacing.

• The pores and un-melted particles cause reduction in tensile strength and strain.

Self-developed SLM 150 equipment[132]Wu et al. ()AlSi10MgLaser power 175 W, scanning speed mm/s, hatch spacing 0.65 mm, island size 6 mm.Tensile, in-situ compression testing

• Long cell-like structures are formed in the printed samples owing to the high cooling rate of the process.

• The Al within the eutectic grows epitaxially on the pre-existing Al cell resulting in further epitaxial growth of the Al cell formed above the eutectic.

• Si precipitates present across the Al-matrix inhibits dislocation motion within the large Al grains.

Concept Laser M2 system[133]Yan et al. ()AlSi10MgLaser beam diameter 100 µm, laser power of 400 W, layer thickness 30 µm, argon atmosphere.Compression, computed tomography

• Lattices with cell sizes 3&#;6.5 mm were very thin for a low volume fraction of 5%, which tended to break during printing.

• The printed samples showed good geometric agreement with the CAD model.

• The compressive modulus and strength of the printed samples directly proportional to the volume fraction of the lattice cells and inversely proportional to the unit cell sizes.

EOSINT M280[134]Yang et al. ()A357Laser power 750 W, scanning speed mm/s, hatch rotation 90°, build plate temperature 35 °C.
Build orientation: Horizontal, Vertical.
Heat Treatment: Directly aged at 160 °C for 8 h; Stress-relieved at 300 °C for 2 h; Stress-relieved and solution treated at 543 °C for 1&#;8 h, quenched and aged at 160 °C for 8 h.Tensile, porosity

• Anisotropy in ductility between horizontally and vertically built samples decrease with solution heat treatments carried out for longer periods of time.

• Negligible coarsening of the columnar grains was observed for all heat treatment conditions.

• The stress relieved sample displayed highest elongation to fracture, primarily owing to the break-up of the Si network into fully dispersed Si particles.

Concept Laser X-line machine[26]Zaretsky et al. ()AlSi10MgBuild orientation: XY, Z.
Heat treatment: T5 stress relieving at 300 °C for 2 h.Dynamic and quasi-static tensile

• Fracture of the printed samples at different tensile rates reflect a change in fracture mode from rate-independent ductile mode to rate-dependent brittle mode.

• At high plastic strain rate range, the yield strength of the printed samples was strain rate sensitive.

EOSINT M280 system[135]Zhang et al. ()AlSi10MgLaser power 490 W, scanning speed mm/s, layer thickness 40 µm, hatch spacing 0.1 mm, hatch rotation 90°, argon atmosphere.
Heat treatment: Stress relieved at 300 °C for 2 h; Solution treated at 530 °C for h, water quenched, and aged at 170 °C for 12 h. Fatigue, tensile

• Heat treatment reduces fatigue property due to the coarsening of Si precipitates.

• For most of the fractured surfaces, the crack initiation sites indicated a presence of surface or subsurface defects.

• The as-built samples display higher fatigue property compared to heat treated samples.

Self-developed SLM system (LSNF-2)[136]Zhou et al. ()AlSi10MgLaser power 400 W, scanning speed mm/s, layer thickness 30 µm, hatch spacing 0.19 mm.
Heat treatment: T6 solution treated at 520 °C for 0.5&#;4 h, water quenched, and aged at 160 °C for 1&#;24 h.Hardness

• Eutectic structure up to 4 μm in size containing tiny needle-like semi-coherent Si particles were observed within the Al cells.

• Embedded spherical nanoscale Si particles and segregated Mg and Fe were observed along the cell and grain boundaries of primary Al. The π-Al8Si6Mg3Fe precipitates were also identified along the boundaries.

• Peak hardening was observed after ageing at 160 °C for 6&#;10 h, and remained relatively unchanged up to 24 h treatment time.

EOS M280[137]Zhou et al. ()AlSi10MgLaser power 300 W, scanning speed 800 mm/s, laser spot size 80 µm, hatch spacing 0.13 mm, layer thickness 30 µm, volumetric energy density 62.5 J/mm3, argon atmosphere, build plate temperature 150 °C.
Heat treatment: Stress relieved at 300 °C for 2 h and water quenched; solution treated 535 °C for 1 h, water quenched, and aged at 190 °C for 10 h.Tensile

• Stress relieving post heat treatment was effective for eliminating residual stresses.

• The printed samples exhibited tensile strength of 273.2 MPa and plasticity of 15.3%.

SLM 280 HL[138]

Understanding die casting

From engine blocks to door handles, die casting is a fast, accurate, and repeatable metal production technique suitable for large or small parts. Die casting parts have an excellent surface finish, and the process is compatible with a range of non-ferrous metals.

Because of the high startup costs associated with die casting, the process is typically used for high-volume production, where the scale of manufacturing makes up for the high machinery and tooling costs. Die cast prototypes and low-volume production runs are harder to obtain, as it is in the economic interests of die casting companies to work with customers placing bulk orders. However, 3ERP currently provides a unique die casting solution for customers wishing to place smaller die casting orders.

This article takes an in-depth look at metal die casting, explaining the suitable materials, surface finishes, and applications for the process.

 

What is die casting?

Die casting is a type of metal casting that uses high pressure to force molten metal into a mold cavity formed by two dies. It shares traits with the plastic manufacturing process of injection molding.

Within the larger metal casting landscape, die casting is one of the most popular techniques due to its accuracy, high quality, and level of detail. The broader category of metal casting, which has existed for thousands of years, contains many different processes that use a mold to form liquid metal. Historically, such a process usually involved pouring the liquid metal into the mold with the aid of gravity &#; and many metal casting processes still work this way. Die casting, however, is a relatively new form of metal casting, introduced in the 19th century, and it uses pressure instead of gravity to fill the mold cavity.

Die casting is sometimes called high-pressure die casting, due to the amount of pressure &#; typically 10&#;140 megapascals &#; used to force the metal into the mold cavity. The related process of low-pressure die casting (LPDC) is less common. Die casting typically falls into one of two categories: hot-chamber die casting and cold-chamber die casting, which are suitable for different types of metal. However, there are also other more niche types of die casting, such as semi-solid metal casting (SSM).

 

Cast Aluminum: Everything You Need to Know

Cast aluminum is a specific aluminum that is formed by casting technique. There is a wide application of cast aluminum due to its lightweight yet good strength. Cast aluminum could be seen in both daily life and industrial applications, such as cast aluminum cookware, cast aluminum chair legs, cast aluminum pumps, and more.

As a professional casting company, we can produce custom cast aluminum parts following your drawing&#;s specifications. There are several aluminum casting processes available at our foundry, including aluminum die casting, aluminum gravity casting and aluminum sand casting. Each casting process has its special advantages, and we can recommend a best suitable casting process according to the design of the aluminum part.

What is Cast Aluminum?

 

Cast aluminum refers to aluminum that has been heated to its melting point before pouring it into molds for specific shapes or forms. The casting process involves heating aluminum until its melting point has been reached, then pouring it in an appropriate mold where it cools and solidifies to produce desired forms or shapes. After casting, post operations such as trimming and surface grinding are performed to achieve net shape castings.

Benefits of Cast Aluminum

Cast aluminum, particularly from manufacturers, offers a range of benefits for various applications. Here&#;s a closer look at the advantages of cast aluminum:

Complex Design Capability

Cast aluminum has its ability to creat parts into complex shapes, no matter how intricate the design is. For its excellent fluidity of aluminum alloys, thet can fill mold cavities completely, and an exact solid cast piece is formed after solidification. 

Lightweight Yet Strong

Aluminum is known for its high strength-to-weight ratio. Parts made from cast aluminum can provide the required strength for great working performace, while maintaning light weig

ht part. This is not available when parts made from other casting materials such as cast steel or cast iron. This benefit makes cast aluminum a good application especially for automotive and aerospace industries.

Excellent Corrosion Resistance

When exposed to atmospheric conditions, aluminum can naturally form an oxide layer, this protects it against corrosion. So, after casting, cast aluminum parts have excellent corrosion resistance, which make them an ideal choice in harsh or corrosive environments, like marine applications or outdoor furniture. If there is a higher requirement, cast aluminum parts could be further anodized or powder painted to improve its enchace its corrosion resistance capacity.

Faster Speed of Production

The casting process of aluminum parts is always faster than other manufacturing process, such as machining or welding fabrication process. As most of the aluminum casting processes are automated, once the molds are prepared, the production process of cast aluminum parts is very fast. Cast aluminum can provide shorter lead times while high quality products.

Cost-effectiveness for Manufacturing

Even with an intial investment in mold, due to the great production speed and less material waste, the cost per cast aluminum part is very economical. Besides, cast aluminum has the ability to creat a simple piece in complex shapes, and reduce or remove the need for post machining, which lower the production cost in further step.

The Casting Processes for Aluminum

 

1. Low / High Pressure Die Casting

Low Pressure Die Casting (LPDC) is the casting process that can produce cast aluminum parts at low pressure, typically between 20 psi and 100 psi. In this process, aluminum is melted and then tranferred into a mold under low pressure until the aluminum solidifies. Cast aluminum parts made from this process can achieve good dimensional accuracy even in medium to high volumes. It is particularly suitable for making cast aluminum parts in thicker wall thickness.

High Pressure Die Casting (HPDC), as its name implies, creats cast caluminum parts at high pressure, typically between 10,000 and 15,000 psi. In this process, molten aluminum is injected into a mold under high pressure fastly. By high pressure die casting, thin-walled cast aluminum parts with complex shapes could be made. Besides, it also allows for high volume production. The strength of cast aluminum made in this process is the best among all the aluminum casting processes.

2. Gravity Die Casting

Gravity Die Casting, sometimes referred to as permanent mold casting, involves pouring molten aluminum into metal molds using gravity for permanent cast aluminum production. Molds made of steel or cast iron typically can support useable multiple cycles, which make gravity die casting an economical medium-to-high volume production method. Cast aluminum parts made from this process can achieve improved mechanical properties and finer surface finishes than sand casting method.

3. Sand Casting

As one of the most versatile casting processes available today, sand casting is not limited to make cast steel and cast iron parts, it can creat cast aluminum parts as well. Cast aluminum parts with intricate geometries are usually made in sand casting process, which is challenging by other casting methods. Aluminum sand casting process involves creating a mold from sand mixture, then pouring molten aluminum into it for solification. Next, the mold is broken away to take out the finished cast aluminum part. This process prpvides flexibility on mold design, so it supports both small and large cast aluminum parts with intricate shapes. While the surface is rougher when compared with die casting process.

Common Cast Aluminum Alloys

 

Because of the excellent mechanical properties and casting ability, cast aluminum is widely used by many industries. At Foundry, we have the capability to produce cast aluminum parts in different alloys, including A356, A360, A380, A383. They have unique chemical compositions, each alloy shows district advantages for different applications.

A356 Aluminum Alloy

A356 aluminum alloy is the most common material in aluminum gravity casting. The T6 heat treatment can further improve its strength and will be helpful for machining operation. The main chemical elements of A356 alloy include aluminum, magnesium (0.02-0.45%), silicon (6.5-7.5%) and other elements. Due to its good castability, welding ability and corrosion resistance, it is widely used in aluminum gravity casting process to creat parts with high strength and ductility. A356 castings are widely used in automotive and aerospace applications, as well as other industries.

A360 Aluminum Alloy

The A360 aluminum alloy mainlt consists of elements like aluminum, magnesium (0.4-0.6%), silicon (9-10%) and copper (6%). These compositions increases its strength and corrosion resistance when compared to other metals. A360 can offer good pressure tightness, which is critical for fluid-handling components. The excellent castability of A360 and its aesthetic surface finish makes it a good choice for casting housings, connectors and complex automotive components.

A380 Aluminum Alloy

A380 is a widely used cast aluminum alloy that contains aluminum, silicon (7.5-9.5%), copper (3-4%) and other elements such as iron, nickel and zinc. It is a versatile die casting material due to its high thermal conductivity and fluidity.

A383 Aluminum Alloy (ADC12)

A383, also known as ADC12, is also a common die cast aluminum alloy. Its composition differences can improve its casting characteristics when compared with A380 alloy. This alloy includes elements like copper, silicon, and aluminum (9.5-11.5%).

How To Select a Right Casting Process for Aluminum?

When selecting a right casting process for aluminum parts, it is necessary to evaluate both the usage of the part and the material properties of cast aluminum alloy. 

Design Complexity

The complexity and detail of any design play an essential part in selecting an optimal casting process. High-pressure die casting specialises in producing parts with intricate geometries and tight tolerances, making it ideal for creating aluminum parts with fine details and high accuracy. So, when the cast aluminum parts have a high requirement on dimensional accuracy and surface finish, high pressure die casting is the best choice for high volume production. For simpler or thicker designed parts, gravity die casting or sand casting may offer more cost effective solutions. Besides, sand casting is also suitable for large cast aluminum parts in small volume production.

Production Volume

Production volumes is also a necessary consideration factor for cast aluminum parts production. For high-pressure die casting, it is only cost effective for high volume production runs due to its high investment on the mold cost. Of course, it is worth to mention that the production efficiency is also very high. Medium volume projects might consider gravity die casting. While for low and prototype runs, sand casting may offer advantages due to reduced tooling costs, although its per-unit costs are higher.

Material Properties and Performance

For its superior strength-to-weight ratio and corrosion resistance of aluminum alloys, they are widely used in casting production. Casting process will further affect the properties. For example, high pressure die casting creates denser microstructures which enhance mechanical properties but increase porosity. Gravity die casting provides excellent material integrity which makes this approach ideal for moderate strength applications. While sand casting produces coarser microstructures which may result in parts with lower mechanical properties than expected &#; it is therefore vital that we clearly establish any performance expectations before choosing this form of casting as our final solution!

Surface Finish

The surface finish is also an important factor to consider when selecting an aluminum casting process. High pressure die casting can provide the finest surface quality of cast aluminum parts, and less or no machining is needed after casting. Low pressure die casting sand gravity die casting also offer good surface finish after fine blasting. While sand casting often provides rougher surface finish, which usually need further machining to achieve higher surface finish.

Cost Considerations

Cost factor could not be ignored when selecting a casting process for aluminum parts. High pressure die casting has the advantages of speed, precision and surface finish, but it requires a high tooling investment, and is more ideal for large orders. Gravity die casing and low pressure die casting offer lower tooling cost, but its unit cost is relatively higher. Sand casting is a most econimical selection for low volume production, while its unit cost per part is the highest when compared with other casting processes, and additional machining operation is usually required for closer tolerances or higher surface finish.

Cast Aluminum vs. Forged Aluminum

The fundamental difference between Cast and forged aluminum is easy to understand: Cast aluminum is the aluminum that was melted in a furnace and poured into a mold. Forged aluminum is when the metal is worked in the solid form with the help of specific tools. These two manufacturing processes will yield two materials with very different properties.

Aluminum has a wide range of uses across every major industry, however, it is often difficult to decide which grade is best suited to a specific application. The challenge becomes greater when comparing not only between alloys but also between cast and forged aluminum. Both are fundamentally aluminum alloys which often have the same alloying elements but in different compositions and quantities. However, the applications and material properties vary widely between the two.

Examples of Cast Aluminum Products

 

You may be surprised to find out that many of the commercial products you come in contact with every day may be using cast aluminum parts and components or even be made entirely from cast aluminum.

Car Parts

Due to the amazing strength and light weight of cast aluminum parts, it is very popular in the production of car parts. For example, safety-critical parts like airbag housings or seat-belt retractor spools are made with diecast aluminum. In addition, steering knuckles, which support the wheel bearing, are made with this material. This is an essential part of a vehicle&#;s suspension, so the lightweight material helps to reduce the overall weight of the car without compromising strength or performance.

Lighting Parts

Due to the light weight and good corrosion resistance of cast aluminum, it is always used as the casting alloy for various lighting parts. Cast aluminum lighting parts could be designed and produced by either gravity die casting or high pressure die casting process.

Medical Devices

Many medical devices are also made from cast aluminum, not only due to the strength but also due to its heat resistance. Some of the more common medical equipment you may see made from this metal is parts for various pumps, surgical tools, components for monitors, and even gearboxes for hospital beds.

Firearms

Another popular application for die casting is the production of firearms. While many popular firearms may have plastic components, there are still a number of parts that are created from die-cast metals. Some of these parts may include triggers, trigger guards, trigger safetys, and much more.

Cast Aluminum Cookware

For decades, cast aluminum cookware (flater beater, dough hook, etc)  has been a vital tool in a well-stocked home kitchen. The versatile product is perfectly suited for cooking on the stovetop and baking in the over. It is dishwasher safe, making for a quick and easy clean up. Despite some ridiculous reports, it is safe to use for cooking and poses no health risks at all.

If you&#;re looking for pots and pans made from this material, the good news is they&#;re everywhere. You can find brand-new sets on the websites of major retailers. If a more classic style is what you are after, you can even find vintage cast cookware on eBay.

Cast Aluminum Patio Furniture

When you think about investing in patio furniture you want something attractive, durable, and low-maintenance. If you also want an outdoor ensemble that&#;s available in a variety of styles, finishes, and colors, cast aluminum patio furniture including cast aluminum chair legs may provide you with an ideal setting to enjoy entertaining and relaxing with family and friends.

 

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