Effect of hybrid reinforcement on microstructure and mechanical properties of AZ61 magnesium alloy processed by stir casting method

In this present study, AZ61 magnesium alloys reinforced with a low weight fraction of alumina (Al2O3: 2 wt %) and silicon carbide (SiC: 0.5, 1, 1.5 wt %) nanoparticle hybrid composites were fabricated using the gravitating mechanical stir casting (GMSC) method. The microstructure analysis reveal a monolithic alloy structure composed of alpha-Mg grains with intermetallic secondary (beta-Mg17Al12) phases uniformly distributed at the grain boundaries. The addition of reinforcements to the monolithic alloy reduces their mean size and leads to a breaking down of the beta-Mg17Al12 phases from round to needle like in shape. The hardness, tensile and compressive strength results show a direct relationship with the SiC reinforcement contents, the maximum values obtained the addition being 1 wt% SiC along with AZ61+2 wt%Al2O3 hybrid composite.