Impact on casting die diameter size on microstructure and fractographic studies of Al2024 alloy reinforced with fly ash and SiC hybrid composites

The development of metal matrix composites is important for industrial applications that require lightweight materials with high strength, stiffness, and wear resistance. In this investigation, Al2024 alloy was reinforced with fly ash and silicon (SiC) carbide hybrid composites using the stir-squeeze cast technique. Two sets of composites were fabricated: one with 3 wt% fly ash and 3 wt% SiC, and the other with 3 wt% fly ash, 5 wt% SiC, and 3 wt% fly ash, 7 wt% SiC The composites were prepared using 25 and 75 mm diameter dies. Microstructural characterization of the specimens was performed using scanning electron microscope, X-ray powder diffraction, and energy dispersive X-ray spectroscopy analysis. Mechanical properties, such as yield strength, ultimate tensile strength, and hardness, were determined according to American Society for Testing and Materials standards. The hybrid composites fabricated in the 25 mm diameter cast iron molds exhibited superior mechanical properties compared to those prepared in the 75 mm diameter molds. The addition of fly ash and SiC particulates enhanced the mechanical properties of the Al2024 alloy. These composites showed improved strength, toughness, and ductility.