Effect of Heat Treatment on the Microstructure and Hardness of Novel Ti-6Al-6Mo Alloy Formed by Laser Solid Forming

A novel Ti-6Al-6Mo alloy sample was fabricated by laser solid forming (LSF) using blended elemental powders as raw material. The microstructure of the as-deposited sample was investigated, and the effects of solution and aging treatment on the microstructure and microhardness of LSF Ti-6Al-6Mo alloy were discussed. The results show that the heat treatment conducted in this study has no obvious effect on the morphologies of prior b grains of the alloy. The solution temperature, solution time, and cooling method after solution treatment have a significant effect on the morphology and size of α phase in the prior β grains and the microhardness of the LSF Ti-6Al-6Mo alloy. When the aging time exceeds 4 h, the microstructure and microhardness of the alloy change little with aging time. Based on the precipitation mechanism of the primary α laths and secondary α laths and their strengthening effect on the b matrix in LSF Ti-6Al-6Mo alloy under different heat treatment conditions, the influence mechanism of heat treatment on the microstructure and microhardness of LSF Ti-6Al-6Mo was revealed.