Investigation of Microstructure, Corrosion Performance and Mechanical Properties of Mg- 6.5Zn- 7.24Sn- 1.22Ca Alloy

This study investigates the Mg-6.5Zn-7.24Sn-1.22Ca alloy, focusing on its microstructural evolution, corrosion resistance, and mechanical performance under varying thermal and mechanical treatments. The alloy was cast under an argon environment, homogenized at 400°C for 18 hours, and hot rolled at 400°C with a 15% thickness reduction. Microstructural analysis through XRD, SEM-EDS, and optical microscopy revealed grain refinement, phase redistribution, and reduced porosity after rolling. Corrosion behavior in 3.5% NaCl solution, assessed via electrochemical techniques and weight loss measurements, indicated superior corrosion resistance in the homogenized condition due to reduced micro-galvanic coupling. Rolling, however, increased corrosion susceptibility due to strain-induced defects. High-temperature ( 200°C- 350°C ) tensile tests at strain rates of 10-4 and 5×10-4 s-1 demonstrated that tensile strength decreases with temperature, driven by dynamic recrystallization and grain boundary sliding. Strain rate variations revealed increased tensile strength at higher rates due to enhanced dislocation density and strain hardening. These findings highlight the interplay between processing conditions, strain rates, and alloy performance, offering insights for optimizing magnesium alloys for advanced engineering applications.