Effect of magnesium solubility in eutectic Al–Si matrix SiC composites on the mechanical properties

This study explores the combined influence of magnesium (Mg) alloy content (0–1.5 wt%) and silicon carbide (SiC) (0–4 wt%) on the mechanical and tribological properties of stir-cast Al-Si composites. The uniform dispersal of SiC within the alloy matrix is confirmed by the microstructural analysis, contributing to improved material properties. The mechanical characterization revealed that hardness and ultimate tensile strength (UTS) increased with the addition of Mg and SiC. Specifically, for unreinforced Al-Si composites, UTS values increased from 158.8 MPa to 191.3 MPa and further to 217.8 MPa as Mg content rose from 0 to 1.5%. In SiC-reinforced composites, UTS improved significantly, reaching 207 MPa with 2% SiC and 217.8 MPa with 4% SiC at 1.5% Mg. Wear tests conducted under varying loads (15–45 N) and speeds (150–450 RPM) demonstrated that wear rates consistently decreased with increasing Mg and SiC contents. These results emphasize the combined effect of Mg and SiC in significantly enhancing the wear resistance and mechanical properties of Al-Si matrix composites, making them appropriate for high-performance applications.