Development of aluminum composite reinforced with selected agricultural residues

Abstract

The use of agricultural residue has been considered an economic and environmentally friendly approach for development of aluminium composites. In this study, Al powder (Al) was reinforced with coconut shell ash (CSA), rice husk ash (RHA), and cassava peel ash (CPA) for enhanced physicomechanical performance of the resulting composites. Five samples (Ao–Al, A1–Al + 15RHA, A2–Al + 5CSA + 5RHA + 5CPA, A3–Al + 15CPA, and A4–Al + 15RHA) were prepared in a two-step stir-casting technique and characterized based on physical, mechanical and metallurgical properties. Microstructural analysis revealed that all the particles bonded well with the aluminum alloy. The densities of samples A1, A2, A3, and A4 reduced by 4.78%, 7.75%, 11.44%, and 14.76%, respectively compared to the control sample Ao while porosities rose by 2.1%, 2.23%, 2.56%, and 2.98% respectively. Sample A2 has the highest tensile strength (39.84 MPa) and hardness (120 HBR) which denote 33.60% and 64.27% enhancement compared to the unreinforced sample. These observations can be attributed to the presence of intermetallic compounds such as Fe3Si and Al6Fe present in the composites as well as uniformly distributed and strongly bounded reinforcement within the aluminum matrix. The composite made from the combination of the three reinforcements gave the best physicomechanical properties and therefore recommended for engineering applications.