Fabrication, mechanical properties, and microstructural analysis of Al/SiC-bagasse ash hybrid composites

The growing need for lightweight and high-strength materials in automotive, aerospace, and structural applications has encouraged research on hybrid aluminum matrix composites (AMCs) reinforced with sustainable waste materials. However, few studies have combined industrial and agricultural by-products to improve both mechanical performance and environmental sustainability. This study focuses on the fabrication and characterization of Al6063-based hybrid composites reinforced with silicon carbide (SiC) and bagasse fly ash (BFA) using the stir casting process at 400 °C. The reinforcement levels ranged from 7.5 to 10 wt% SiC and 7.5–12 wt% BFA to examine their combined effect on the composite’s mechanical and microstructural properties. The results showed remarkable improvements compared to the unreinforced Al6063 alloy. The tensile strength increased by 32% to 82.95 MPa, while the compressive strength rose by 29% from 295 MPa to 380.10 MPa in the composite containing 10% SiC and 12% BFA. The highest hardness value of 96.9 HV was obtained for the sample with 7.5% SiC and 10% BFA, due to uniform particle distribution and restricted dislocation motion. Microstructural analysis using optical and scanning electron microscopy confirmed an even dispersion of reinforcements at moderate levels, with slight clustering at BFA contents above 10%. No harmful Al₄C₃ phase was detected, as the silica in BFA promoted the formation of stable aluminum-silicon-oxygen compounds. The improved mechanical properties were mainly attributed to effective load transfer, dislocation blocking, crack resistance, and grain refinement. Overall, combining SiC and BFA provides a cost-effective and eco-friendly approach for producing high-performance Al6063 hybrid composites suitable for automotive body panels, aerospace components, and load-bearing industrial structures.