Fabrication, Characterization, and WEDM Optimization of Al-7175 Hybrid Composites with Ceramic and Sustainable Waste Reinforcements

Aluminum metal matrix composites are valued for their lightweight nature, high performance, and favorable thermal expansion characteristics, preparing them to be suitable for aerospace, defense, automotive, athletic training equipment, and electronics applications. Al-7175 alloy, widely employed in aerospace for advancing structural components, is selected in this pilot study as a base material. reinforcements included varying weight percentages of Al2O3 (2, 4, 6, and 8%), SiC (three levels), and palm kernel shell ash (PKSA) as a sustainable waste-based additive. The composite are fabricated by stir casting method, and test specimens are prepared in accordance with international standards to evaluate stiffness, tensile strength, impact resistance, and wear behavior. The results revealed that incorporating Al₂O₃, SiC, and PKSA enhanced stiffnesses per the additives added in MMCsby1%, 1.5%, 1.6%, and 1.7% (as per the wt.%) and tensile strengthby8%, 10%, and 40, impact resistance by7%, 34%, 25%, and 42%, reduced wear by 2.4%, 22%, and 7.2%due to the synergistic effect of these reinforcements. An L9 orthogonal array and design of experiments (DOE) approach are employed to optimize Wire Electrical Discharge Machining (WEDM) parameters, for minimal surface roughness and optimal material removal rate (MRR). MRR reduction is linked to a higher Ton, voltage, wire feed rate, and Toff settings, with long-range producing higher MRR at minimum reinforcements level but increases in surface roughness. Optimal WEDM parameters are determined as Ton = 5, Toff = 5, voltage = 75, and wire feed = 6, enabling efficient and precise production ofAl-7175 hybrid metal matrix composites (HMMCs) reinforced with Al2O3, SiC, and PKSA across different weight fractions.