Investigating the Microstructure, Tensile Strength, and Acidic Corrosion Behaviour of Liquid Metal Stir Casted Aluminium-Silicon Carbide Composite

Abstract

The main objective of this investigation is to study the microstructural features and evaluate the tensile strength, hardness, and acidic corrosion resistance of liquid metal stir casted aluminium-silicon carbide (Al-SiC) composite. As reinforcement for the Al alloy matrix, SiC particles were added to the matrix in the percentages of 0%, 10%, and 20%. The microstructure of Al-SiC composite was studied using optical microscope. The effect of addition of SiC particles on tensile strength and hardness of Al-SiC composite was analyzed.. There were significant improvements in tensile strength and hardness for Al–SiC composite reinforced with 20% SiC particles compared to unreinforced Al–SiC composite, and those improvements were of 14.70% and 26.88%, respectively. The evolution of harder SiC islands in the ductile matrix of aluminium alloy reinforce the Al-SiC composite which enhances the strength and hardness of Al-SiC composite. A weight loss method was used to determine corrosion rate. The samples of Al-SiC composite material were immersed in HCl, HNO3, and H2SO4 solutions for immersion times of 30 hours, 56 hours, and 80 hours. It was found that the weight % of reinforcement had the largest contribution to corrosion rate with 49.86% to that of acidic solution with 29.88%, followed by immersion time with 8.85% and acidic solution with a contribution of 29.88% to the corrosion rate. The Al-SiC composite developed using 20 wt. % of SiC particles showed higher corrosion rate due to the interfacial region formed due to the addition of greater wt % SiC particles to the pure alloy.