With an inherent lowest density and distinct solubility with enhanced mechanical behavior reason, the magnesium alloy composite is extensively used in the auto and aero sectors. The processing of magnesium alloy found micro‐cracks and voids between the oxidation spot, which fails properties. Through the sulfur hexafluoride (SF6) atmosphere, the AZ91D alloy hybrid nanocomposites are synthesized with 10 wt% alumina (Al2O3) and 0, 3, 6, and 9 wt% of silicon carbide (SiC) nanoparticles via a liquid state process with 400 rpm stir speed followed by vacuum die casting. The effect of SiC actions on physical behavior, microstructural formation, and mechanical properties of AZ91D/10 wt%Al2O3, AZ91D/10 wt%Al2O3/3 wt% SiC, AZ91D/10 wt% Al2O3/6 wt% SiC, and AZ91D/10 wt% Al2O3/9 wt% SiC composites are studied and its results compared with cast AZ91D alloy. Due to the actions of SiC in AZ91D/10 wt%Al2O3, the composite density conforms to the rule of mixture, and the void and micro‐cracks are limited (less than 1%) by the impact of the casting process, as evidenced in the microstructural illustration. An effect of 10 wt% Al2O3 and 9 wt% SiC contents in AZ91D facilitates maximum tensile strength of 181 MPa, improved elongation percentage of 2.2%, optimum hardness of 85HV, and superior impact toughness of 21.8 J/mm2, which is higher than the all other compositions.