Dry sliding wear behaviour of Al 7075/Al2O3/B4C composites using mathematical modelling and statistical analysis

The present research work reports the fabrication of aluminium alloy 7075(AA 7075) reinforced with particles of aluminium oxide (Al2O3) and boron carbide (B4C) using stir casting technique. The research was carried out in two stages. In the first stage, orthogonal array and signal-to-noise ratio were employed to study the influence of process parameters on dry sliding wear behaviour of composites reinforced with varying weight percentage of Al2O3 (8,10 and 12 wt%) particles. In the second stage optimization, optimum weight percentage ratio of Al2O3 (12 wt%) is selected from the first stage and reinforced with different weight percentages of B4C (2, 3 and 4 wt%). A three level face centred composite design experiment was developed using response surface methodology. Analysis of variance and confirmatory experiments were performed to validate the predictive model. The surface plots revealed that wear rate increases with an increase in load and sliding distance. On the other hand wear rate decrease with increase in reinforcement percentage. In the case of sliding velocity, the wear rate decreased initially but after reaching critical value it increased. The wear was also analysed using scanning electron microscopy analysis which confirms the trend by the predictive model. The results also confirmed that by adding B4C the wear of alumina reinforced composites have significantly reduced.