Impact of Microstructural Anisotropy of As-Cold-Sprayed Cu Deposits on its Annealing Effect

Cold spraying is being developed as effective and promising additive manufacturing process. However, how to create a deposit by cold spraying with comparable properties to bulk material is still challenge. It is well known that post-spray annealing is an effective process to enhance the deposit properties. In this paper, copper deposits are cold-sprayed at three different sets of spray conditions corresponding to three mean particle velocities of 578, 745, and 807 m/s. The tensile strength, thermal conductivity and electrical conductivity are measured at three different directions to clarify the anisotropy of deposit properties, which are parallel to gun moving direction and other two perpendicular directions. Furthermore, the influence of post-spray annealing on the anisotropy effect is also investigated by examining the effect of spray conditions and annealing conditions on the deposit properties at three different directions. The results clearly demonstrate the anisotropy of as-deposited Cu. Although it can be found that post-spray annealing significantly improves the properties of the as-sprayed deposits and reduces anisotropy of Cu deposit properties, the microstructure of the as-sprayed initial Cu deposit presents a significant effect on final annealed deposit. Therefore, an optimized cold-sprayed deposit will benefit manufacturing of a deposit with comparable properties with bulk by cold-spraying combined with post-spray annealing.