Achieving excellent wear and corrosion properties in laser additive manufactured CrMnFeCoNi high-entropy alloy by laser shock peening

Abstract

The present work aims to fabricate CrMnFeCoNi high-entropy alloy (HEA) possessing outstanding wear and corrosion properties via laser additive manufacturing (LAM) and subsequent laser shock peening (LSP). The surface morphology , microstructure, microhardness and residual stress of LAM-fabricated specimen were characterized before and after LSP. Additionally, sliding wear and electrochemical corrosion experiments were conducted to evaluate the suitability of LSP for improving wear and corrosion resistance . Results indicated that friction coefficients and wear rates of LAM-fabricated specimens obviously decreased after LSP. Both untreated and LSP-treated specimens displayed uniform wear mechanisms, including abrasive and adhesive wear , while the wear damage level of the high-energy LSP-treated specimen was the mildest. Moreover, LSP-treated specimens exhibited lower corrosion current density and higher corrosion potential as compared with the untreated specimen, suggesting an enhancement in corrosion resistance. The hardened surface layer had positive effects on inhibiting furrow and spalling to resist material removal, and the compressive residual stress enhanced the adhesion of tribo-layers on the worn surface to protect the underlying layer from further damage. The grain refinement and compressive residual stress synergistically contributed to form compact passive films, thereby restraining the aggression of corrosive ions to enhance the corrosion resistance. • LAM-fabricated CrMnFeCoNi HEA is treated by LSP. • LSP improves the wear and corrosion resistance of LAM-fabricated CrMnFeCoNi HEA. • The wear and corrosion mechanisms of CrMnFeCoNi HEA treated by LSP are discussed.