Enhanced cavitation erosion and electrochemical corrosion properties of additively manufactured Hastelloy C276 coating by ultrasonic shot peening

To augment the erosion and corrosion resistance of the additively manufactured Hastelloy C276 coating, it was subjected to ultrasonic shot peening (USP) treatment. Subsequently, cavitation erosion and electrochemical corrosion experiments were conducted. This study explored the influence of USP under various parameters on cavitation erosion/corrosion behavior and erosion mechanism through microhardness testing, analysis of roughness changes, micromorphology observation, microstructure characterization, mass loss monitoring, and measurement of electrochemical parameters. The results show that with an increase in shot peening duration, the hardness of the coating increases by 37.1% due to the refinement of the surface structure, and the depth of the hardened layer reaches 206.9 μm. The mass loss rate of the USP-treated coating is reduced by 43.9% compared to the initial coating. The damage mechanism of cavitation erosion involves cavity growth and crack propagation. The surface layer of the USP-strengthened coating exhibits a smaller grain size and increased hardness, significantly enhancing its resistance to damage. Notably, the cavitation erosion behavior of Hastelloy C276 shows a preferential removal of the Mo element. USP treatment also enhances the coating’s performance in electrochemical corrosion experiments, proving to be an effective method for further enhancing the resistance of Hastelloy C276 to cavitation erosion and corrosion.