This research affair to synthesize the magnesium alloy (AZ91) hybrid nanocomposites with 0.5wt% titanium dioxide (TiO2) and 2.5, 5, and 7.5wt% of silicon carbide (SiC) nanoparticles through a semisolid stir cast route under argon (inert) nature and its particle distribution enhanced with uniform stir speed of 400rpm as well as the casting defects reduced by using nature of inert. The excellence of semisolid stir processing with SiC exposure on AZ91/TiO2 composite is analyzed with physical, surface morphological and mechanical exploits. Compared to aluminium-based composites, this composite weight is less, with an acceptable level of voids (less than 1.5%). An effort of processing, the microstructure proved their SiC and TiO2 appearance as uniform. The AZ91/0.5wt%TiO2/7.5wt% SiC exploited maximum hardness of (84±0.8HV), impact toughness of (16.3±0.3J/mm2), and excellent strength (251±5MPa) with reduced elongation percentages of (4.5%). This optimum property sample will be planned for automotive roof frame applications. © 2024 Informa UK Limited, trading as Taylor & Francis Group.