Cold Spray Additive Manufacturing of Ti6Al4V: Deposition Optimization

Abstract

CSAM deposition of Ti6Al4V is a challenging task, and high-quality deposits conforming to the AM application standards have not been developed so far. In our study, two distinct feedstock Ti6Al4V powders with different morphology and microstructure were used, and their influence on the key CSAM deposition parameters was investigated. The deposits were analyzed in terms of microstructure (including porosity), electrical conductivity, as well as tensile properties before and after heat treatment. The process gas temperature was found as the most influencing parameter, and the spherical plasma atomized powder resulted in a higher deposit density and electrical conductivity than the crystalline powder at 1100 °C and 50 bars. Using the optimal deposition parameters and heat treatment, unprecedented tensile properties for CSAM Ti6Al6V deposits were achieved, exhibiting 887 MPa yield strength and 929 MPa ultimate tensile strength, values that satisfy the ASTM B381 requirements for Ti6Al4V forgings, and a substantial 4.74% elongation.