Development of a micro-alloyed bio-Mg alloy with high strength-ductility, promising corrosion behavior via rotary swaging

Magnesium (Mg) has good biocompatibility and biodegradability, and similar elastic modulus and density to those of human bone, endowing it with broad application prospects in the field of medical bone implant materials. However, the trade-off between strength, ductility and corrosion behavior of Mg alloys largely limits their practical applications. Based on our previously developed Mg0.5Zn0.2Ge0.05Ca alloy, this study tried to optimize the mechanical properties of MgZnGeCa alloy with promising corrosion behavior via rotary swaging at room temperature. After rotary swaging, the yield strength of the alloy achieved 263.44 MPa, which is 99.98 MPa higher than that of the extruded state. The improvement in strength is mainly attributed to grain refinement and dislocation strengthening. Furthermore, it can still maintain relatively high plasticity, with ∼19% of elongation, which is ascribed to the formation of 〈 c + a〉 dislocations during swaging that coordinates the strain along c -axis direction. Additionally, a comparable low corrosion rate and uniform corrosion is examined for swaged sample compared to the extruded alloy but with a slightly higher corrosion rate during the initial 1 day of immersion, which is mainly caused by the high strain accumulated in forms of twins and dislocations. This study presents a feasible strategy via swaged micro-alloyed alloy to obtain a high comprehensive property for orthopedic applications.