High Rate Cold Spray Deposition of Titanium

VRC Metal Systems recently developed a high deposition rate cold spray process for titanium and titanium alloys for use in additive manufacturing and repair in collaboration with the South Dakota School of Mines and Technology. In the cold spray process, micron-sized metal particles are accelerated supersonically toward a substrate, where collision results in mechanical interlocking and metallurgical bonding. During the process, the metal particles never reach melting temperatures but are fused through adiabatic shearing processes. Therefore, substrate heating is minimized, dimensional stability is maintained, and unwanted thermal effects such as oxidation, undesirable phase formation, and heat affected zone formation are avoided, making cold spray ideal for in-situ repair and large-scale additive manufacturing in atmospheric conditions. Cold spray deposited titanium exhibits low porosity and exceptional mechanical strength (>60ksi) and adhesion (>10ksi), where grain size and structure can generally be maintained from the powdered state to the as deposited condition. After deposition, the added material can be subtractively processed through traditional machining operations, resulting in a repaired or remanufactured component that meets or exceeds the original equipment manufacturing specifications. In this study, cold spray deposition of Ti and Ti-6Al-4V was investigated using optimized processing parameters and optimized powder microstructure to analyze the effects on mechanical properties of the as-deposited specimen. We further demonstrate the feasibility of a 10 lb/hour build rate using titanium cold spray through a combined theoretical and experimental approach. VRC also presents the current state of the art in its cold spray equipment and hybrid manufacturing systems to transition this cold spray additive manufacturing and repair capability to industrial and military partners.