STATISTICAL ANALYSIS ON TRIBOLOGICAL BEHAVIOUR OF AN AL ALLOY 7075 – AL2O3 COMPOSITES

Abstract

Al alloy 7075 reinforced with Al2O3 particles of three different sizes (63,102, and 165 μm) were fabricated through the stir casting method. Dry sliding wear tests were conducted to evaluate the influence of load, sliding velocity and particle size on the wear loss and coefficient of friction of the composites using a pin-on-disc wear testing rig. Tests were conducted according to L9 Taguchi orthogonal array for three different loads (10, 30, and 50 N) at three different velocities (0.837, 1.674, and 2.512 m/s) for a constant time period of 30 minutes. The results showed that the wear increased with increasing load and sliding velocity whereas the coefficient of friction increased with increasing sliding velocity. On the contrary, the coefficient of friction decreased with increasing load. Composites reinforced with coarse Al2O3 particles exhibit superior wear resistance. It was found that the load was the most dominant factor influencing the wear loss and coefficient of friction followed by sliding velocity and particle size. A Scanning Electron Microscope (SEM) was used to study the morphology of the worn surfaces of the pins.