Elevated temperature wear of submicron Al₂O₃ reinforced 6061 Aluminum composite

The effects of load and temperature on wear behavior of 6061 Aluminum alloy matrix composite reinforced with 20% Al₂O₃ (submicron) particulates against AISI 4041 steel disc were studied at elevated temperatures ranging from 25°C to 300°C. Mild and severe wear regions separated by a transition region were observed at all temperatures with a difference of two orders of magnitude between mild and severe wear. The critical loads observed at 100°C, 200°C and 300°C were 40 N (2 MPa), 30 N (1.53 MPa) and 15 N (0.76 MPa) respectively indicating that wear resistance of the composite decreases with increase in temperature. Scanning electron microscopy revealed that wear was accompanied by extensive thermal softening of the matrix, in addition to particulate fracture due to high shear strain generated from the contacts and material transfer to the counterface. The wear rates were reduced in the mild wear regime due to oxidation of the iron counterface and deposition of oxides on the contact surfaces evident by EDS analysis.