Microstructural Evolution and Corrosion Characterization of Heat-Treated and Thermo-Mechanical Processed Mg-0.45Zn-0.45Ca Alloy for Biomedical Applications

The present work evaluates how heat treatment, hot rolling, and aging affect the microstructure and performance of Mg-0.45Zn-0.45Ca alloy for biodegradable implant applications. Hot rolling refines the grain size from 127 µm to 38 µm, while aging promotes a finer and more uniform precipitate distribution. Mechanical testing shows that ultimate tensile strength increases from 166 MPa (as-cast) to 231 MPa (rolled-aged), and Rockwell hardness improves by 121 %. Corrosion tests in simulated body fluid (37 °C) show improved corrosion resistance, with the potentiodynamic polarization rate decreasing from 0.634 mm/year to 0.183 mm/year. A CO₂-regulated SBF system maintained physiological pH during immersion, improving the reliability of corrosion assessment. The experimental results provide valuable insights into the effects of heat-treatment and thermo–mechanical processing and microstructure–performance relationships of the Mg-Zn-Ca alloy, highlighting its potential application as a biomedical implant material.