Vacuum-Featured High-Performance SiC-Blended Hybrid AZ91E Alloy Composite by Liquid Stir Solidification: Characteristics Measured

The AZ91E grade magnesium alloy is specialized for automotive and aerospace applications. It offers excellent castability for creating complex shapes through the liquid metallurgy route and boasts a high strength-to-weight ratio, good stiffness, and one-third the weight of steel. Traditional liquid stir processes associated with gravity casting for creating magnesium alloy composite casts often fail to deliver their intended functional benefits due to the formation of voids and microcracks caused by oxidation. However, by introducing argon (Ar) into the process, the hybrid AZ91E alloy nanocomposites, created by loading 1.5 weight percentages (wt%) of nanoalumina (Al₂O₃) particles combined with 0, 2, 4, and 6 wt% of nanosilicon carbide particles through a vacuum-assisted liquid stir solidification process at a stirring speed of 400 rpm, have shown promise. The vacuum-assisted multi-ceramic combination, featuring SiC configuration on the surface morphology, actual density, percentage of porosity formation, tensile and impact toughness, and Vickers hardness, has been investigated. The surface morphology analysis has confirmed that the reinforcements are homogeneously dispersed in the AZ91E matrix. The vacuum-featured hybrid AZ91E alloy nanocomposite exhibits reduced porosity, and the hybrid AZ91E/5 wt% Al₂O₃ alloy nanocomposite with 6 wt% of nano-SiC features less than one percentage of porosity while enhancing tensile and impact strength to 178 ± 4 MPa and 20.1 ± 0.5 J/mm², and a better Vickers hardness number of 87 ± 3 HV.