Optimization of mechanical and tribological properties of Al composites reinforced with selected agricultural waste ash for lightweight engineering applications

Abstract

 Agricultural residues have been applied as reinforcements in metal matrix composites because of their low cost and the possibility of reducing environmental pollution. In most of these applications, the mixing ratios follow a parametric approach making optimization important for maximum deployment of agricultural residue. In this study, tribological and mechanical properties of Al composites reinforced with coconut shell ash (CSA), rice husk ash (RHA), and cassava peel ash (CPA) were optimized following a multi-objective optimization technique. Eleven samples were prepared in a two-step stair casting technique with the selected filler at 15wt.% and 85wt.% Al-powder as the matrix. The tensile strength, percentage elongation, wear rate, and elastic modulus of all synthesized samples were analyzed. The results show that the samples containing 5wt.%RHA + 5wt.%CSA + 5wt.%CPA + 85wt.%Al and 10wt.%RHA + 2.5wt.%CSA + 2.5wt.%CPA + 85wt.%Al gave optimum mechanical values (133.106 MPa, 8.175%, and 109.945 GPa) while samples with 2.5wt.%RHA + 10wt.%CSA + 2.5wt.%CPA + 85wt.%Al gave optimum wear rate (0.074Ml/Nm). Statistical analysis showed that the three fillers (RHA, CSA, and CPA) are significant implying that they are responsible for the variation in physicomechanical properties of the composites. The optimum physico-mechanical propeeties were 133.106 MPa, 8.175%, 109.945 GPa, and 0.074Ml/Nm and obtained at proportions of 5wt.%RHA + 5wt.%CSA + 5wt.%CPA + 85wt.%Al and 10wt.%RHA + 2.5wt.%CSA + 2.5wt.%CPA + 85wt.%Al and 2.5wt.%RHA + 10wt.%CSA + 2.5wt.%CPA + 85wt.%Al.