Dry sliding wear of Al alloy 2024-Al 20 3 particle metal matrix composites

Abstract

In the present investigation, Al 2024-15vol.%Al 20 3 particulate (average size, 18 μm) composites were fabricated using the liquid metallurgy route. The wear and friction characteristics of AI alloy 2024 and Al 2024-15vol.%Al 20 3p composite in the as-extruded and peak-aged conditions were studied using a pin-on-disc machine (with a steel disc as the counterface material). The worn surfaces, subsurfaces and the debris were analysed in a scanning electron microscope. The performance of the 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 unreinforced alloy seizes while the composite does not within the tested range employed. In the as-extruded condition, the presence of A1 20 3 particles is not particularly beneficial as they fracture and result in extensive localized cracking and removal of material from the surface. In the peak-aged condition, however, while the unreinforced alloy exhibits severe plastic deformation and undergoes seizure, there is no significant 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 materials show the presence of an iron-rich layer.