The Effect of Post Heat Treatment on the Microstructure and Mechanical Properties of Cold-Sprayed Zn-6Cu Deposits

To explore the feasibility of preparing Zn alloy bulk, Zn-6Cu deposit was prepared by cold-spraying additive manufacturing. Microstructure, tensile and wear behavior were investigated before and after heat treatment. Cold-sprayed Zn-6Cu deposit was constituted by irregular flattening particles and pores after heat treatment. Zn-6Cu deposits were composed of Zn and CuZn5 phases in addition to ZnO phase regardless of heat treatment, but the full width at half maximum of both the CuZn5 and the Zn phase were varied. The yield strength and ultimate tensile strength of Zn-6Cu deposits after post heat treatment were, respectively, increased from 83.8 +/- 28.7 MPa and 159.6 +/- 44.5 MPa to 89.4 +/- 24.4 MPa and 223.8 +/- 37.1 MPa. Fracture morphology after tensile testing exhibited main features of dimples, pores and cleaving particles. The friction coefficient and wear rate of Zn-6Cu deposits were increased after heat treatment, and the corrosive wear exhibited a lower friction coefficient and wear rate than the dry wear due to the lubricant of simulated body fluid. Grooves and localized delamination were the main wear features of Zn-6Cu deposits regardless of both the heat treatment and wear condition. This result indicates a potential application of cold-sprayed Zn-6Cu deposits comparable to the casting ones.