Improvements in Microstructure, Mechanical and Degradation Properties of Mg–Y–Zn–Zr Alloy via Extrusion for Implant Applications

The microstructure and degradation behavior of a low-alloyed Mg-1.2Y-Zn-0.3Zr alloy were investigated for potential implant applications by permanent mold casting and hot extrusion. The phase composition and microstructure were characterized using scanning electron microscopy and X-ray diffraction. Degradation properties were investigated by using loss-weight tests and electrochemical measurements. The results show that the W-phase (Mg₃Zn₃Y₂) exhibited segregation at the grain boundaries. Dynamic recrystallization significantly refined the alloy's grain structure. After hot extrusion, the average grain size was 2.96 μm, with tensile strength, elongation, and degradation rate values of 255 MPa, 27%, and 3.78 mm y^-1, respectively, which implies that the enhanced mechanical and degradation properties are attributed to grain refinement and grain boundary segregation strengthening. This may provide a promising solution for implant material development.