Dry Sliding Wear Behaviour of Aluminium Al-Si12Cu/TiB2 Metal Matrix Composite Using Response Surface Methodology

An aluminium Al-Si12Cu/TiB2 metal matrix composite was fabricated using the liquid metallurgy route, and its dry sliding wear characteristics were investigated under various sliding parameters. The titanium diboride (TiB2) particles (10 wt%, average size 50-60 mu m) were incorporated into the matrix and its microstructural characteristic was examined. A five-level central composite design experiment was developed using response surface methodology; parameters such as load, velocity and sliding distance were varied in the range of 10-50 N, 1-5 m/s and 500-2500 m, respectively. Dry sliding wear tests were performed as per the experimental design using a pin-ondisc tribometer at room temperature. Significance tests, analyses of variance and confirmatory tests were performed to validate the developed model. Study of the microstructural characteristics revealed uniform dispersion of the reinforcement particles throughout the composite. The regression result showed that the developed model performed well in relating the wear process parameters with the response and predicting the wear behaviour of the composite. The surface plot showed that wear rate increased with increasing load at all velocities and distances, and decreased with increasing sliding distance. In the case of velocity, the wear rate decreased initially, increasing after the transition velocity had been reached. Scanning electron microscopy analysis revealed severe wear at a high load due to a higher level of deformation of the composite surface.