Synergistic improvement of strength and elongation of Zn-Mg alloys as orthopedic implants through ECAP

Abstract The Zn-1.47 wt% Mg alloy achieved a superior combination of tensile strength (399 MPa) and elongation (19.5%) through complete refinement of its eutectic structure via equal-channel angular pressing (ECAP). Microstructural analysis revealed that this enhancement was driven by two key mechanisms: (1) dynamic recrystallization (DRX), which significantly reduced grain size, and (2) the formation of needle-like and particle-like precipitates within Zn grains, contributing to grain boundary and precipitation strengthening. Notably, ECAP at 250 °C and then at 150 °C proved more effective than direct deformation at 150 °C in achieving full refinement of eutectic structure. The fragmented eutectic structure not only enhanced strength through second-phase strengthening but also improved ductility by minimizing stress concentration. Furthermore, the refined microstructure led to improved corrosion resistance, with reduced susceptibility to localized corrosion. Compared to pure Ti, the ECAP-processed Zn-Mg alloys demonstrated superior biocompatibility and osteogenic potential, making them promising candidates for orthopedic implant applications.