Ti6Al4V alloy is an ideal lightweight structural metal for a huge variety of engineering applications due to its distinguishing combination of high specific mechanical properties, excellent corrosion resistance and biocompatibility. Laser Powder Bed Fusion (LPBF) provides very different mechanical properties from that of casting or wrought Ti6Al4V. The inherent specificities of the LPBF process, as the layer-by-layer building strategy; the powder feedstock; the melting phenomena and thermal gradients, define the mechanical properties, once they will dictate the microstructural features (e.g. grain size, crystal growth direction, residual porosity and defects, among other).
Property | Stainless Steel 316 L (Cast) | F75 CoCrMo Alloy (Cast) |
Cortical Human Bone |
Ti6Al4V Alloy (Wrought) | Aluminium Alloy A357 (Cast) |
---|---|---|---|---|---|
Density (g/cm3) | 8.0 | 8.8 | 1.5–2 | 4.4 | 2.7 |
Yield strength (MPa) | 205 | 500–1500 | - | 830–1070 | 265–275 |
Ultimate tensile strength (MPa) | 515 | 900–1800 | 130–190 | 920–1140 | 331–351 |
Tensile modulus of elasticity (GPa) | 195–205 | 200–230 | 10–30 | 100–110 | 70–75 |
Elastic elongation (%) | 10–40 | 4–13 | - | 10–15 | 6 |
Company | SLM Solutions GmbH (Germany) |
EOS GmbH (Germany) |
Concept Laser GmbH (Germany) |
Renishaw (UK) |
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Equipment | SLM 125HL [36][60] |
SLM 250HL | SLM 280HL [37][61] |
EOSINT M270 |
EOSINT M280 [38][62] |
EOSINT M290 [39][63] |
M2 cusing [40][64] |
AM 250 |
Build Envelope (mm3) | 125 × 125 × 125 | - | 280 × 280 × 365 | 250 × 250 × 215 | 250 × 250 × 325 | 250 × 250 × 325 | 250 × 250 × 280 | 250 × 250 × 300 |
Laser details | IPG fiber laser 400W |
IPG fiber laser 400W |
IPG fiber laser 400, 700 or 1000W | Yb-fiber laser 200W |
Yb-fiber laser 200 or 400W |
Yb-fiber laser 400W | Fiber laser 200 or 400W |
Yb-fiber laser 200W |
Tensile strength | [6][41][33,65] | [32][42][43][56,66,67] | [44][68] | [45][46][47][69,70,71] | [48][49][50][51][52][21,72,73,74,75] | [53][54][55][76,77,78] | [31][55] | [56][57][58][79,80,81] |
Tensile strain | [6][41][33,65] | [32][42][43][56,66,67] | [44][68] | [45][46][47][69,70,71] | [48][49][50][51][21,72,73,74] | [53][54][76,77] | [31][55] | [56][57][58][79,80,81] |
Young’s Modulus | [6][33] | - | [59][82] | [45][60][69,83] | [49][72] | [54][77] | [56][79] | |
Fatigue behavior | - | [15][32][61]][4,41[,5662],84[63],85[64,86] | [63][85] | |||||
- | ||||||||
[ | ||||||||
50 | ||||||||
] | [ | 51 | ] | [ | 76][73,74,96] | [70][76][90,96] |
Reference | Yield Strength (MPa) |
Tensile Strength (MPa) |
Tensile Strain (%) |
Young’s Modulus (GPa) |
Direction |
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Reference | Condition/Heat Treatment | YS (MPa) | TS (MPa) | TS’ (%) | Microstructure | |||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Benedetti et al. [84][104] | 1015 | 1090 | 10 | |||||||||||||||
Kasperovich et al. | 113 | [31] | - | |||||||||||||||
[55] | Wrought | 927 | 984 | 19.3 | globular α + β (Figure 1a) |
Shunmugavel et al. [6][33] | 964 1058 |
1041 1114 |
||||||||||
As-built | 736 | 1051 | 7 3 |
113 109 |
11.9 | α′ acicular, column width < 0.5 μm (Figure 1longitudinal transversal |
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Vandenbroucke et al. [85][105] | 1125 | 1250 | 6 | 93 | - | |||||||||||||
b) | ||||||||||||||||||
700 °C–1 h–FC (10 °C/min) | 1051 | 1115 | 11.3 | α′ acicular, column width < 1.0 μm (Figure 1c) |
Vrancken et al. [86][106] | 1110 | 1267 | |||||||||||
900 °C–2 h followed by 700 °C–1 h–FC (10 °C/min) |
908 | 988 | 7.3 | 109 | transversal | |||||||||||||
9.5 | elongated primary α grains in a β matrix | ( | Figure 1d) | Edwards et al. [15][41] | 910 | 1035 | 3 | - | transversal | [45][46][65][7,69,70] | [48][49][51][66][21,72,74,87] | [54][55][77,78] | [31][55] | |||||
Fatigue crack analysis | ||||||||||||||||||
HIP (900 °C/100 MPa–2 h) followed by 700 °C–1 h–FC (10 °C/min) | 885 | 973 | 19 | elongated primary α grains in a β matrix (Figure 1e) |
Vilaro et al. [34][58] | 1137 | 1206 | 7.6 | 105 | longitudinal | - | [32][61][62][63][64][67][4,56,84,85,86,88] | [63][85] | [45][46][47][65][7,69,70,71] | [49][51][72,74] | [54][77] | [31][55] | |
Hardness | [7][68][2,3] | [64][86] | - | [45][69] | ||||||||||||||
Vilaro et al. [34][58] | As-built | 1137 | 1206 | 7.6 | α′ acicular (Figure 2a) |
962 | 1166 | 1.7 | 102 | transversal | [69] | |||||||
730 °C–2 h–AC | 965 | 1046 | 9.5 | α′ acicular embedded in α + β phases (Figure 2b) |
Koike et al. [87][107] | 850 | 960 | 6.8 | - | [ | ||||||||
950 °C–1 h–WQ | - | |||||||||||||||||
944 | 1036 | 8.5 | α′ acicular, α and β | (Figure 2c) | 89] | Anatoliy et al. [44][70][90] | [68[57][80] | |||||||||||
] | 1200 | 1280 | 2.4 | - | - | |||||||||||||
1050 °C–1 h–WQ | 913 | 1019 | 8.9 | α′ acicular (Figure 2d) | Density | Gong et al. [45][69][7][68][2,3] | [4][42][31,66] | - | [60][71][ | 109872 | 1237] | 8.8[83 | 109 | |||||
Huang | - | |||||||||||||||||
et al. [57][80] | As-built | , | 91 | ,92] | [69][89] | [54][ | 97077] | [31][73 | 1191] | 5.4 | α′ acicular (Figure 3a)[55,93] |
[58][81] | ||||||
Microstructure | Leuders et al. [32][56[6]7][74][3,33,94] | ][[32][42][43][62][75][ | 100856,66,67,84,95] | [44][59][68,82] | [45][46][47][60][65][72][7,69,70,71,83,92] | [48]21[49][,7250][,7352][ | 108069 | 1.6] | -[,75,89] | [53][55][76[76 | -] | |||||||
800 °C–2 h–AC | 1010 | , | 1073 | 17.1 | less fine α′ acicular embedded in α + β phases (Figure 3b) | 78,96] | [31][55] | [58][77][78][81,97,98] | ||||||||||
Heat treatments | Wysocki et al. [ | 88][108] | [32][43][61][62][63][64][4,56,67,84,85,86] | [44][63][68 | 1150,85] | 1246 | 1.4[48] | -[ | longitudinal49 | |||||||||
950 °C–2 h–AC | 893 | 984 | 14.2 | α laths in β matrix (Figure 3c) | ][50][52][21,72,73,75] | [54][77] | [57][80] | |||||||||||
Parameters assessment | [7][41][3, | 127365] | [4][42 | 1421][31,66] | - | 3.2[45][72][ | -69,92] | [70][90] | [31][ | transversal73][55,93] | [58][81] | |||||||
Surface roughness | ||||||||||||||||||
1050 °C–1 h–AC | 869 | 988 | 13.3 | equiaxed and α-equiaxed prior β grains (Figure 3d) |
Kasperovich et al. | [31][55] | 802 | 1062 | 12.7 | - | longitudinal | |||||||
1200 °C–1 h–AC | 897 | 988 | 11.3 | α-equiaxed prior β grains | Rafi et al. [47][71] | |||||||||||||
Vrancken et al. [86][106] | 1195 1143 |
1269 1219 |
5 4.9 |
- - |
Forgedlongitudinal transversal |
|||||||||||||
960 | 1006 | 18.4 | α + β | Mower et al. [49][72] | 972 1096 |
1034 1130 |
- - |
109 115 |
longitudinal transversal |
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Huang et al. [57][80] | 970 | 1191 | 5.4 | - | - | |||||||||||||
Fachini et al. [80][100] | 990 | 1095 | 8.1 | 110 | - |
As-built | |||||
1110 | |||||
1267 | |||||
7.3 | |||||
α′ acicular | |||||
( | |||||
Figure 4 | |||||
a) | |||||
540 °C–5 h–WQ | |||||
1118 | 1223 | 5.4 | - | ||
850 °C–2 h–FC (0.04 °C/s) | 988 | 1004 | 12.8 | α′ acicular, α and β (Figure 4b) |
|
940 °C–1 h–AC followed by 650 °C–2 h–AC |
899 | 948 | 13.6 | long columnar prior β grains (Figure 4c) |
|
1015 °C–0.5 h–AC followed by 730 °C–2 h–AC |
822 | 902 | 12.7 | - | |
1015 °C–0.5 h–AC followed by 843 °C–2 h–FC (0.04 °C/s) |
801 | 874 | 13.5 | α + β | |
1020 °C–2 h–FC (0.04 °C/s) | 760 | 840 | 14.1 | α + β (Figure 4d) |
|
Leuders et al. [32][56] | As-built | 1008 | 1080 | 1.6 | α′ acicular |
800 °C–1h–FC | 962 | 1040 | 5 | α′ acicular, α + β | |
1050 °C–1 h–FC | 798 | 945 | 11.6 | α + β | |
HIP (920 °C/1000 bar)–2 h–FC | 912 | 1005 | 8.3 | α + β |