Additive manufacturing of titanium-base alloys with equiaxed microstructures using powder blends

Abstract

The microstructures and tensile properties of additively manufactured Ti-base alloys were investigated. Ti-6A14V and Co-Cr-Mo alloy powders were blended and used for directed energy deposition of bulk samples containing 5 and 10 wt% Co. The Ti-6Al-4V and 5 wto% Co samples exhibited an a phase at ji grain boundaries, which caused a significant reduction and anisotropy of the tensile ductility. A single-phase beta microstructure exhibiting equiaxed grains with a grain size of 36 1m, random texture, and isotropic tensile properties was obtained for the as-deposited 10 wt% Co sample. These phenomena could be ascribed to the high Co content and the resulting enhanced stability of the ji phase and the constitutional supercooling of the melt-pool.