Effects of bamboo stem ash (BSA) on the physical and mechanical properties of A356/BSA composites fabricated through a stir casting method

This is the authors' abstract. We don't add key points for this paper.

Agro-waste reinforced Aluminium Metal Matrix Composites (AMMCs) present a sustainable and cost-effective alternative to conventional ceramic reinforcements. This study investigates bamboo stem ash particulates (BSAp) characterised by elevated SiO₂ content as reinforcement in A356 aluminium alloy, a system that remains underexplored compared to bamboo leaf ash variants. Composites containing 2.5, 5.0, and 7.5 wt.% BSAp were produced via stir casting and evaluated for physical and mechanical properties per ASTM standards. Incorporation of BSAp progressively reduced composite density while maintaining acceptable porosity levels, confirming casting soundness. Mechanical testing revealed that hardness and tensile strength improved with increasing reinforcement, peaking at 5 wt.% BSAp, where an 18% enhancement in strength-to-weight ratio over the unreinforced alloy was recorded, attributed to grain refinement and effective matrix–reinforcement interfacial bonding. Beyond this threshold, 7.5 wt.% addition induced particle agglomeration and elevated porosity, diminishing both strength and ductility. These findings establish BSAp as a viable low-density, silica-rich reinforcement candidate, and demonstrate that optimised A356/BSA composites hold considerable promise for lightweight structural applications in the automotive and aerospace sectors.