Fabrication and Characterisation of Aluminium Alloy/Rice Husk Ash Composites for Lightweight Automobile Wheels

This study focuses on the development of an aluminium alloy composite reinforced with rice husk ash (RHA) for automobile wheel applications. Aluminium piston scrap was used as the base matrix, and RHA was introduced at 5%, 10%, and 15% weight fractions using the stir-casting method. The produced composites were subjected to hardness, tensile strength, impact energy, density, and wear tests to evaluate the influence of RHA on the aluminium alloy’s mechanical and physical properties. Results revealed that the addition of RHA significantly affects the alloy’s behaviour. At 5 wt% RHA, the hardness was increased by 12.7%, tensile strength by 5.9%, and impact energy by 8.3% when compared with the control sample. The density of the composite samples decreased by 1.2%, indicating an initial weight reduction. At 10 wt% RHA, the composite exhibited the highest performance, with hardness increasing by 18.2%, tensile strength by 16.7%, and impact energy by 25%, while density decreased by 2.8%, indicating an optimal strength-to-weight ratio. Furthermore, X-Ray Fluorescence (XRF) analysis of the raw materials confirmed that the rice husk ash contained 80.02% SiO2, with minor quantities of Al2O3, Fe2O3, and CaO, making it an effective reinforcement material. The developed composite showed increased silicon content in the alloy from 19.6% to 21.2% after reinforcement, confirming the successful integration of silica-rich RHA into the aluminium matrix. Overall, the density consistently decreased as the RHA content increased, while mechanical properties improved up to the 10 wt% level before declining. The study concludes that 10 wt% RHA provides the best balance between lightweight characteristics and mechanical strength, making it a promising material for sustainable and high-performance automobile wheel production.