Development and Characterization of Semisolid-Formed Al-5%Cu-4%Mg/SiC Composites for Lightweight Structural Applications

Aluminum-based metal matrix composites (MMCs) are attractive for lightweight structures and components due to their low density and high specific strength. This study reports the synthesis of Al-5%Cu-4%Mg/SiC composites via an integrated route combining in-house alloy preparation, high-speed stir casting (5000 rpm), and semisolid compression forming at 640 °C under 150 tons. In contrast to prior works that relied on commercial alloys, pure aluminum ingot, pure copper wire, and Al-13%Mg master alloy were used to enable precise control over matrix–reinforcement interactions. Silicon carbide particles (50–200 µm) were incorporated at 5% and 20% volume fractions with argon-assisted dispersion, achieving uniform distribution and strong interfacial bonding. Semisolid forming refined the microstructure, producing fine, globular grains that enhanced mechanical performance. Standardized testing revealed significant improvements in hardness and tensile strength over as-cast counterparts. The results confirm the effectiveness of the proposed method for enhancing structural performance, highlighting its suitability for applications demanding lightweight and durable materials.