Tribological Behavoiur of Silicon Carbide/ Rice Husk ash Reinforced Al7075 Hybrid Composites Using Optimization Techniques

Abstract

In this paper, aluminium alloy Al7075 was reinforced with silicon carbide (SiC) particles and rice husk ash to improve hardness and wear resistance. The SiC particulate and rice husk ash composition in composite were taken in five different proportions such as 3%, 6%, 9%, 12% and 15% for % of SiC particulates and 2%, 4%, 6%, 8% and 10% for % of rice husk ash. Nine different compositions to cater the above proportions were fabricated using stir casting technique. Microstructure examination was conducted on the prepared specimen using optical microscope to determine the homogeneity of reinforced particle distribution. The tribological properties were examined by measuring the wear on the prepared specimen using pin on disc apparatus. The input parameters considered were materials factor such as % of SiC and % of rice husk ash and mechanical wear factors such as load applied, speed of rotation and sliding distance. The design of experiment technique, central composite design (CCD) was employed for conducting experiments with different combination of parameters. Empirical relationship was devised to predict wear of the composite specimen in terms of parameters such as % SiC, % of rice husk ash, load applied, speed of rotation and sliding distance. The empirical relations adequacy was tested using Analysis of variance (ANOVA). The direct and interaction effect of input parameters on wear were analyzed which helps to determine the significance of these parameters. Microstructure examinations were conducted to analyze assimilation and uniform distribution of reinforcement particles in prepared composites. Optimization of process parameter was obtained for minimum wear using genetic algorithm.