Microstructure and Mechanical Property of Ti–5Al–5Mo–5V–3Cr–1Zr Alloy Fabricated by Selective Laser Melting with a Preheated Substrate

The high solidification rate of selective laser melting (SLM) induces a nonequilibrium microstructure in as‐fabricated Ti alloys. Herein, a metastable β Ti–5Al–5Mo–5V–3Cr–1Zr alloy is successfully fabricated by SLM on a preheated substrate at 700 °C. The effects of preheating temperature on microstructure and mechanical properties of as‐fabricated specimens is systematically studied. The phase identification and electron microscopic results demonstrate that the 700 °C preheating temperature enables the transformation of metastable β structure into an α + β structure with massive amounts of nanosized α precipitates. Consequently, the SLM‐fabricated specimen after preheating process possesses higher ultimate tensile strength and hardness at 1440 MPa and 8.24 GPa, respectively. This work shows an alternative for SLM to tackle nonequilibrium microstructure and to increase the strength of metastable Ti alloys by introducing high temperature preheating.