Microstructural, mechanical and tribological behaviour of powder metallurgy processed SiC and RHA reinforced Al-based composites

This study aims to fabricate and evaluate the behaviour of Aluminium matrix composites (AMCs) reinforced with Rice husk ash (RHA) and Silicon carbide (SiC). The AMCs consisting of varied weight ratios of RHA (0, 5, 10 & 15 wt.%) and SiC (10 wt.%) were produced using the powder metallurgy process. The microstructural characteristics were examined by Scanning Electron Microscope (SEM), X-ray Diffraction (XRD) and Energy Dispersive X-ray spectroscope (EDS) elemental mapping. Dry sliding wear, hardness, density and percentage of porosity were evaluated for the produced composites. Dry sliding wear tests were carried out on the AMCs to evaluate the wear loss and coefficient of friction as function of RHA content by sliding against a steel counterface. Furthermore, sliding loads, sliding distances and sliding velocities were selected as control factors with three levels and the wear loss was selected as a response to evaluate the dry sliding performance of the Al, Al + 10% SiC and Al + 10% SiC + 10% RHA composites. Microstructural observation depicted a homogenous dispersion of SiC and RHA particles in the composite except for 15% RHA composite where clustering of RHA particles were observed. The mechanical and tribological study showed that the hardness and wear properties of the AMCs increased with an increase in RHA contents up to 10% and then decreased. The worn surface and wear debris was analysed using SEM and wear mechanism was reported.