Fabrication and Characterization of AA7075/Al ₂ O ₃ /Graphene Hybrid Composites via Friction Stir Additive Manufacturing

Lightweight metal matrix composites (MMCs) are widely utilized across marine, defense, aerospace, and automotive sectors due to their high strength‐to‐weight ratio, wear resistance, stiffness, and thermal stability. This study investigates a hybrid composite of AA7075 reinforced with a constant total reinforcement of 10 wt%, while varying the individual weight percentages of graphene nanoplatelets (GNPs) and aluminum oxide nanoparticles (Al ₂ O ₃ ). The composite was successfully fabricated via a multi‐layer friction stir additive manufacturing (FSAM). Among five different samples, the sample with 0.4 wt% GNPs and 9.6 wt% Al ₂ O ₃ shows significant improvements over the unreinforced base alloy: a 47.7% increase in tensile strength (230.8–340.83 MPa), a 32% improvement in Vickers hardness (67.6–89.33 HV), and a 24.6% increase in compressive strength (208.9–260.28 MPa) indicate the potential of FSAM to improve the structural and mechanical characteristics of the material. Microstructural characterization using field emission scanning electron microscopy (FE‐SEM) and optical microscopy (OM) confirms that the mechanical strength is significantly improved due to sound interlayer bonding and uniform reinforcement distribution within the stir zone. This study demonstrates a substantial improvement in mechanical properties, thereby increasing the suitability of the composite for industrial applications.