DRY SLIDING WEAR OF AL-ALLOY 2024-AL2O3 PARTICLE METAL-MATRIX COMPOSITES

In the present investigation, Al 2024-15vol.%Al2O3 particulate (averag e size, 18 mu m) composites were fabricated using the liquid metallurg y route. The wear and friction characteristics of Al alloy 2024 and Al 2024-15vol.%Al2O3p, composite in the as-extruded and peak-aged condit ions were studied using a pin-on-disc machine (with a steel disc as th e counterface material). The worn surfaces, subsurfaces and the debris were analysed in a scanning electron microscope. The performance of t he composite in the as-extruded condition is slightly inferior to that of the unreinforced alloy. However, in the T6 condition, although the wear rates of two materials are initially comparable, the unreinforce d alloy seizes while the composite does not within the tested range em ployed. In the as-extruded condition, the presence of Al2O3 particles is not particularly beneficial as they fracture and result in extensiv e localized cracking and removal of material from the surface. In the peak-aged condition, however, while the unreinforced alloy exhibits se vere plastic deformation and undergoes seizure, there is no significan t change in the mechanism in the case of the composite. Except in the case of the peak-aged unreinforced alloy, worn surfaces of all other m aterials show the presence of an iron-rich layer.