Microstructure Evolution and Mechanical Properties of Ti-25Ta Alloy Fabricated by Selective Laser Melting and Hot Isostatic Pressing

Abstract:

Ti-25Ta alloy samples were fabricated by selective laser melting, and the relative density, microstructure, microhardness and tensile properties of the as-built and hot isostatic pressing (HIP)-prepared samples were characterized. Results show that the track width and penetration depth are increased with the increase in laser power, and the surface morphology is improved. The maximum relative density improves from 95.31% to 98.01% after HIP process. Moreover, the microstructure is refined into the lath martensite and cellular grains with the increase in input power. After densification treatment, the subgrain coalescence occurs and high angle grain boundaries are formed. In addition, HIP process stabilizes the microhardness and enhances the tensile strength and elongation.