Effect of Particle Size on Wear of Particulate Reinforced Aluminum Alloy Composites at Elevated Temperatures

The present paper describes the effect of particle size on operative wear mechanism in particle reinforced aluminum alloy composites at elevated temperatures. Two composites containing zircon sand particles of 20-32 mu m and 106-125 mu m were fabricated by stir casting process. The dry sliding wear tests of the developed composites were performed at low and high loads with variation in temperatures from 50 to 300 A degrees C. The transition in wear mode from mild-to-severe was observed with variation in temperature and load. The wear at 200 A degrees C presented entirely different wear behavior from the one at 250 A degrees C. The wear rate of fine size reinforced composite at 200 A degrees C at higher load was substantially lower than that of coarse size reinforced composite. Examination of wear tracks and debris revealed that delamination occurs after run in wear mode followed by formation of smaller size wear debris, transfer of materials from the counter surfaces and mixing of these materials on the contact surfaces. The volume loss was observed to increase with increase in load and temperature. Composite containing bigger size particles exhibit higher loss under similar conditions.