Enhancing Mechanical Properties and Corrosion Resistance of GW63K Magnesium Alloy via Ultrasonic Surface Rolling Process

In this study, an ultrasonic surface rolling process (USRP) was employed to enhance the surface performance of a GW63K-T6 magnesium alloy. The results show that the USRP induces a gradient-distributed {10–12} deformation twin structure in the surface layer, with twin density decreasing progressively from the surface inward. Following USRP treatment, surface microhardness increased by approximately 40%, yield strength (YS) by about 26%, and ultimate tensile strength (UTS) by roughly 11%. Corrosion resistance was also significantly improved, as evidenced primarily by a weight loss reduction of approximately 50% after 120 h of immersion corrosion and further supported by polarization curves with a positive shift in corrosion potential and a decrease in current density for the USRP-treated samples. The observed improvements in mechanical properties and corrosion resistance are closely associated with the gradient twin structure. These findings suggest that the USRP is a promising technique for the simultaneous enhancement in mechanical and corrosion properties of Mg-RE alloys, although further investigation is needed to fully elucidate the underlying mechanisms.