Effect of Silicon Dioxide-Reinforcement on the Mechanical Properties of AZ91 Alloy through Equal Channel Angular Pressing

This study aims to investigate the enhancement of AZ91 magnesium-aluminum alloy by reinforcing it with 3 wt.% silicon dioxide and processing it through Equal Channel Angular Pressing (ECAP). Specimens with 0 wt.% and 3 wt.% silicon dioxide are fabricated using gravity casting and mechanical stirring, followed by T4 heat treatment and ECAP. Microstructural analysis using scanning electron microscopy (SEM) and X-ray diffraction (XRD) reveals that silicon dioxide is uniformly dispersed, refining the grain structure and dissolving the β-phase, leading to improved ductility. Mechanical testing shows that adding 3 wt.% silicon dioxide increases the yield strength (YS) by 15.26% and the ultimate tensile strength (UTS) by 23.65% after T4 treatment. ECAP further enhances these values by 19.92% and 41.35%, respectively, while increasing hardness by 15.95%. The improved strength-to-weight ratio makes this alloy suitable for automotive, aerospace, and electronics applications, particularly for lightweight structural components.