Wear and friction behavior of near eutectic Al-Si+ZrO2 or WC particle composites

Dry sliding wear and friction behavior of cast near eutectic Al-Si alloy and composites containing 5 vol.% WC or ZrO2 particles were studied by means of a three pins-on-disk (steel) apparatus over a load rang of 18-180 N and a sliding speed of 1 m/s. The experimental results showed that the composites exhibited a superior wear resistance in comparison to that of the unreinforced alloy at load range of 18-180 N. The contact surface temperature increased with increasing applied load. The coefficients of friction for all the tested materials decreased with increasing applied load front 18 to 90 N. However, at load levels of 90-180 N, the coefficients of friction increase as the load increases. SEM investigations revealed that in the load range of 18-90 N, the worn surfaces of the composites reinforced either by WC or ZrO2 were covered by iron oxides, which provided in situ lubrication. However, at load above 90 N, the WC or ZrO2 particles fractured and lose their ability to support the load. Therefore, the wear rates of the composites significantly increased. (C) 2003 Elsevier Ltd. All rights reserved.