Heat Treatment Effects on the Microstructure, Mechanical and Wear Properties of an Al 2024 Cold Spray Additive Manufactured Deposit

The impact of high-speed micron-sized metallic particles during cold spray additive manufacturing (CSAM) often leads to non-uniform plastic deformation, resulting in work hardening effects that can cause brittleness, poor mechanical properties, and anisotropy in the deposits. This study aimed to characterize the wear, mechanical properties, and mechanical anisotropy of 2024 aluminum alloy deposits and investigate the effects of heat treatments (annealing, solution, aging treatment) on improving these properties. The results revealed that the mechanical property anisotropy of the As-sprayed deposits was not significant. Specifically, the tensile strength of the As-sprayed deposits measured at angles of 0º, 45º, and 90º from the spraying direction are 58 MPa, 52 MPa, and 41 MPa, respectively. Annealing was found to decrease wear resistance and hardness but had a positive impact on mechanical properties. Solution and aging treatment proved to be effective in improving wear resistance. For the solution-treated deposits, the measured tensile strength and elongation at angles of 0º, 45º, and 90º from the spraying direction are 108 MPa, 114 MPa, and 101 MPa, and 6.5%, 5.8%, and 4.8%, respectively. It is worth noting that heat treatment improves the bonding quality, however, the presence of pores generates during the heat treatment limits further improvements in mechanical properties. Overall, this study highlights the importance of heat treatments in enhancing the mechanical properties, wear resistance, and mechanical anisotropy of 2024 aluminum alloy deposits produces through CSAM.