Rapid Densification of Ti-6Al-4V by Cold Spray and Spark Plasma Sintering

Cold spray is an additive manufacturing technique which allows solid state deposition of materials under atmospheric conditions. Cold spray produces dense, oxide-free deposits of ductile metals, but does not achieve 100% densification of harder, high temperature alloys such as Ti-6Al-4V. In this study it is shown that spark plasma sintering (SPS) can be used to fully densify cold sprayed Ti-6Al-4V. The effect of cold spraying the Ti-6Al-4V powder on subsequent SPS is compared with sintering the powder by SPS directly. In addition, it is shown how different sintering temperatures and pulse sequences affect the microstructure and mechanical properties including hardness and shear strength, as measured using a shear punch test. It is demonstrated that a dense, fine-grained structure can be produced through the combination of cold spray and SPS.