Effect of Laser Shock Peening on the Wear-Corrosion Synergistic Behavior of an AZ31B Magnesium Alloy

Laser shock peening (LSP) is one of the widely used surface processing techniques for tailoring functional behavior of surfaces. LSP has been used to enhance friction, wear, and mechanical properties. However, understanding of LSP-treated surfaces involving tribological contacts in electrochemically active environments is limited because the mechanism of wear-corrosion interactions (tribocorrosion) for such surfaces is still unclear. In the present study, the effect of LSP on the wear-corrosion behavior of an AZ31B Mg alloy is investigated. A zero-resistance ammeter (ZRA) method is utilized to examine the evolution of open circuit potential (OCP) during wear-corrosion analysis. The study finds that the LSP processing can decrease the corrosion potential difference between worn and unworn regions of the surface, thereby mitigating the effect of wear-accelerated corrosion during sliding. The effect of wear-accelerated corrosion is evident from the change in average surface roughness (Sa) of the unworn areas. It is found that understanding the change in surface roughness due to wear-corrosion interactions is necessary to investigate the onset and propagation of galvanic corrosion. Based on these results, the study details the mechanism of wear-corrosion interactions during sliding.