OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 27 No. 3 2025 The addition of SiC reinforcements to 7XXX series alloys has been shown to improve fatigue strength [12]. The incorporation of Al2O3 reinforcements into scrap aluminum alloy wheels affects porosity, hardness, ultimate tensile strength, and ultimate compressive strength [13‑15]. Researchers have reviewed the effect of mixed nanoparticles in base fluids on the properties of nanofluids and machining characteristics, suggesting that nanoparticle size and concentration significantly influence nanofluid effectiveness [16‑19]. Research has also explored the effect of SiC reinforcements on the mechanical properties of A356 composites, including hardness, tensile strength, compressive strength, and elongation [20]. However, the effects of hybrid reinforcement particles on Al7075-T6 alloy remain largely unexplored. Silicon carbide and graphene offer varying benefits as reinforcement materials: SiC is ideal for enhancing hardness and tensile strength, while graphene excels in lightweight, high-strength applications. This study aims to investigate the influence of varying proportions of nanosized SiC and graphene (Gr) on the hardness and tensile strength of Al7075-T6 alloy, prepared using the stir casting method. The study also examines the microstructural and fracture surface analysis of the composites using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX). This research aims to create lightweight, high-performance hybrid metal matrix nanocomposite materials and explore the potential of combining SiC and Gr nanoparticles with Al7075, with a focus on characterizing the mechanical properties of these hybrid materials. Materials and Design Aluminummatrix composites (AMCs) reinforced with silicon carbide (SiC) and graphene are favored for aerospace and automotive applications due to their enhanced mechanical and tribological properties [21]. Graphene’s high strength-to-weight ratio can improve property enhancement, although its poor wettability and tendency to aggregate can be limiting factors [22]. Stir casting and other methods are employed to achieve a homogeneous reinforcement distribution, which enhances the mechanical properties of Al7075 composites [23]. In this study, Al7075-T6 serves as the matrix material, while silicon carbide (30-50 nm) and graphene (5‑10 nm) are used as reinforcements. Reinforcement materials influence the mechanical and physical properties of composites. SiC and graphene are preferred reinforcements for engineering applications due to their distinctive characteristics. Silicon carbide, known for its hardness, thermal conductivity, and resistance to corrosion and chemical attack, is well-suited for high-temperature environments and enhances durability. With a density of 3.22 g/cm³ and a hardness of 2450 BHN, silicon carbide is a rigid, robust material ideal for wear-resistant applications. Graphene, with a low density of 2.2 g/cm³ and a hardness of 110 BHN, is well-suited for strong, lightweight components. Despite its lower hardness compared to SiC, graphene can be used to create flexible, high-strength composites. Graphene’s tensile strength of 130 GPa surpasses that of most materials, benefiting advanced composites that require a high strength-to-weight ratio. The mechanical properties of the cast specimens were characterized using hardness tests (ASTM E10) and tensile tests (ASTM-B557). Hardness was measured using a Brinell hardness tester. Tensile tests were performed on a universal testing machine (UTM). Scanning electron microscopy (SEM) was used to analyze the particle distribution patterns in the composites. Energy dispersive X-ray spectroscopy (EDS) was used to identify the elements present in the specimens. SEM and EDS were performed using a JEOL JSM-IT200 model. The experimental setup for preparing Al7075-based nanocomposites with varying reinforcements is depicted in Fig. 1. Initially, Al7075-T6 ingots weighing 1.5 kg each were obtained. These ingots were then placed in a crucible within the stir casting furnace. The molten metal was heated to 750 °C and maintained at that temperature for 120 minutes. Magnesium powder (1 wt.%) was added to the molten metal to prevent oxidation. Varying combinations of graphene and silicon carbide reinforcements were then introduced into the molten metal. Before introduction, these reinforcements were preheated for 5‑7 minutes. A mechanical stirrer was used to ensure uniform dispersion of reinforcements in the molten metal for fifteen minutes. The slurry that formed on the surface of the molten metal was gradually removed to
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