Dry sliding wear behaviors of Al-25Si-2.5Cu-1Mg alloys prepared by powder thixocasting

The wear performance of an Al-25Si-2.5Cu-1Mg alloy prepared by powder thixocasting was studied using a pin-on-disc machine. LM13 and an Al-25Si-2.5Cu-1Mg alloy prepared by conventional ingot metallurgy were also investigated for comparison. The sliding tests were performed under ambient conditions and without lubricant. During the tests, the applied load was increased stepwise until wear seizure occurred. Experimental data reveal that the powder thixocast alloys exhibit better wear performance than that of conventional alloys, especially under heavy load conditions and following T6 treatment. This work demonstrates the potential of the new method, powder thixocasting, for fabricating hypereutectic Al-Si-X alloys with a high wear resistance. Moreover, the variation in the wear rate with the applied load for the alloy can be divided into three regions. The mechanisms associated with these wear regions were discussed based on the investigations of the worn subsurface and the wear debris.