Effect of Laser Remelting on Thermal Stability of Ti-6Al-4V Alloy Prepared by Laser Powder Bed Fusion
The effect of laser remelting(LR)on the microstructure property and thermal stability of Ti-6Al-4V alloy prepared by laser powder bed fusion(LPBF)was investigated.The results show that after LR treatment,the thermal stability of the α'phase within the LRed-Ti-6Al-4V titanium alloy samples is significantly improved,and the temperature at which β-Ti phase appears is up from 500 ℃ to 700 ℃ .After heat treatment,the grains in LPBF-Ti-6Al-4V titanium alloy grow continuously,and obviously appear to be"short bar-like"and"coarse lamellar"at the temperature above 700℃;while the grains in the melting zone of the surface layer of the LRed-Ti-6Al-4V sample are still maintain equiaxial,and the relatively uniform and fine needle-like microstructure are observed in the melting zone and heat affected zone above 700℃.The surface microhardness of those two groups of samples decreases with the increased temperature,especially significant at 700 ℃ and 850 ℃ respectively.It is found that the rapid coarsening of β-Ti grains is the main reason for the falling down of hardness.
additive manufacturing3D printinglaser powder bed fusion(LPBF)laser remelting(LR)Ti-6Al-4Vannealing heat treatmentthermal stability
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