Heat treatment effect on microstructural evolution of cold spray additive manufacturing Ti6Al4V

Cold spray additive manufacturing (CSAM) has great industrial potential due toits high deposition rate and the possibility of building metallic alloys and compositeparts once the process is conducted in a solid state, preserving many rawmaterials properties. A material highly studied for CSAM is the Ti6Al4V alloy,which is used in medical implants and aeronautical structural components. Ithas a matrix of two phases $(α + β)$ with different crystallography arrangements,compact hexagonal, and body-centered cubic, which can tailor the mechanicalproperties according to its volumetric percentage. To improve CSAM-ed materialductility and strength and homogenize its residual stress, heat treatments (HTs)have been employed. These HTs sinter the deposited particles, enhancing theircohesion and other properties. This study focuses on the effect of the HT parameterson the characteristics of CSAM-ed Ti6Al4V freeform parts. HT reduces thehardness from 385 in as-sprayed condition to around 320 HV$_{0.3}$,conserving theporosity close to 4.0%, and increasing the HT temperature from 600 to 1000 °Cimproved the amount of phase β in the α grains boundaries. The findings of thisstudy will provide valuable insights into the impact of HT on the mechanicalproperties and microstructure of CSAM-ed components, thereby aiding in theoptimization of this manufacturing process for the Ti6Al4V alloy.