Selective laser melting of near-α titanium alloy Ti-6Al-2Zr-1Mo-1V:Parameter optimization, heat treatment and mechanical performance

This paper presents a comprehensive study conducted to optimize the selective laser melting(SLM)parameters and subsequent heat-treatment temperatures for near-α high-temperature titanium alloy Ti-6 Al-2 Zr-1 Mo-1 V(TA15),which is widely used in the aerospace industry.Based on the surface morphology and relative density analysis,the optimized process parameters were:laser power from 230 W to 380 W,scan speed from 675 mm/s to 800 mm/s,scan spacing of 0.12 mm,and layer thickness of0.03 mm.The effects of the laser power and the layer thickness on the phase constitutions,microstructure features,as well as room-temperature and high-temperature(500℃) tensile properties,were then studied to obtain an in-depth understanding of SLM-built TA15.Six typical temperatures(650,750,850,950,1000 and 1100℃) covering three representative temperature ranges,i.e.,martensite partial decomposition temperature range,martensite complete decomposition temperature range and above βtransus temperature,were subsequently selected as heat-treatment temperatures.The heat treatmentmicrostructure-mechanical property relationships of SLM-built TA15 were elucidated in detail.These results provide valuable information on the development of SLM-built TA15 alloy for industrial applications,and these findings are also beneficial to additive manufacturing of other near-α Ti alloys with desirable high-temperature properties.