Synergistic effects of Sn addition and friction stirring on microstructure and performance of ZE41 mg alloy

The limited mechanical strength, poor corrosion resistance, and suboptimal wear performance of ZE41 magnesium (Mg) alloy hinder its widespread use in critical applications such as aerospace and biomedical implants. Addressing these challenges requires innovative approaches to tailor the microstructure and phase distribution of the alloy. This study investigates the quantitative impact of tin (Sn) addition (4 wt%, 8 wt%, 12 wt% and 16 wt%) on the microstructure, mechanical properties, corrosion resistance, and wear behavior of ZE41 magnesium (Mg) alloy processed through friction stirring. Microstructural analysis via optical microscopy, FESEM, XRD and Raman spectroscopy revealed a progressive reduction in grain size from 113 mu m in the base alloy to 0.8 mu m in the 16 wt% Sn-added alloy, attributed to the suppression of Mg7Zn3RE intermetallic phase at grain boundaries. Hardness measurements showed an increase from 60.34 Hv (base alloy) to 106.95 Hv (16 wt% Sn), while tensile strength improved from 135 MPa to 191 MPa, demonstrating substantial mechanical enhancement. Corrosion studies in simulated body fluid indicated a marked improvement in corrosion resistance, with the degradation rate decreasing from 3.85 mm/year (base alloy) to 0.91 mm/year (16 wt% Sn). Similarly, wear performance improved significantly, with the wear rate reducing from 6.4x 10-5 mm3/N<middle dot>m for the base alloy to 2.1 x 10-5 mm3/N<middle dot>m for the 16 wt% Sn composite. Tribological analysis indicated a decrease in the coefficient of friction from 0.48 to 0.31. The predominant wear mechanisms transitioned from severe delamination and abrasion in the base alloy to milder adhesion and oxidation in Sn-reinforced composites. These results establish that Sn addition, in synergy with friction stirring, dramatically enhances the microstructure and functional properties of ZE41 Mg alloy, making it a promising candidate for advanced structural and biomedical applications.