Solid-state fabrication of WCp-reinforced Stellite-6 composite coatings with supersonic laser deposition

Supersonic laser deposition (SLD) is a relatively new material deposition technique, which combines laser irradiation with cold spray (CS). The solid-state manufacturing of continuous and dense WC/Stellite-6 composite coatings was achieved by SLD in this study. The comparison between the WC/Stellite-6 composite coatings produced by SLD and laser cladding (LC) respectively was conducted with respect to microstructure, phase composition, microhardness, cracking susceptibility, and tribological behaviors, thus to elucidate the role of laser irradiation in the SLD process. The experimental results show that the SLD coating has fewer defects, higher WC content, lower cracking susceptibility and better wear-resistant performance than the counterpart prepared by LC, which benefits from the preservation of microstructures and phase compositions of the feedstock materials due to the relatively low heat involved in SLD process. Moreover, due to the additional heat provided by laser irradiation, the bonding mechanism in SLD evolves from dominant mechanical bonding in CS to coexistence of mechanical and metallurgical bonding.