Simultaneous Optimization of Strength and Bio-Corrosion Resistance in Biodegradable ZX10 Magnesium Alloy via Thermomechanical Processing and Annealing

Abstract

Magnesium alloys are increasingly recognized as promising materials for biodegradable implants due to their low density, biocompatibility, and favorable mechanical properties. However, achieving a balance between mechanical strength and bio-corrosion resistance remains a critical challenge. This study systematically investigates the effects of three thermomechanical processing routes—extrusion (EXT), Equal Channel Angular Pressing (ECAP), and ECAP followed by annealing at 150^∘C for 10 hours (ECAP-A)—on the ZX10 magnesium alloy. EXT produced coarse grains and moderate mechanical and corrosion performance. ECAP refined the grain structure and reduced the Mg₂Ca phase, leading to an 80% increase in hardness, improved yield strength, and enhanced ductility, but at the cost of a doubled corrosion rate due to high dislocation density. ECAP-A mitigated this drawback, reducing the corrosion rate to 1.50 mm/year while maintaining a high yield strength ( > 200 MPa). This improvement was driven by a uniform distribution of the Ca₂Mg₆Zn₃ phase, further dissolution of the Mg₂Ca phase, and reduced dislocation density. These findings establish ECAP-A as an effective strategy to simultaneously optimize strength and bio-corrosion resistance, advancing the ZX10 magnesium alloy as a promising material for biodegradable implants.