Effect of size and volume fraction of particulates on the sliding wear resistance of CuSn composites

The effects of volume fraction and size of particulates on wear resistance of the CuSn/FeCrp composites were studied. Experiments were performed at th e load range of 10-400 N and at a constant sliding velocity of 0.5 ms(-1). Two different material SAE 1050 steel and mullite slider were used as count erface materials. It was seen that at low loads particulate size is effective on the wear rat e. Because, particulates act as load-bearing constituents, and it was detec ted that the wear resistance of the CuSn/FeCrp reinforced Metal matrix comp osites (MMCs) with 62.4 Rm diameter reinforcement size was higher than that of the MMCs with the same volume fraction of FeCrp with 4.3 mum diameter s ize, respectively. The wear rates of the composites worn with a steel slide r gave lower values compared with those worn against a mullite slider becau se of the formation of iron-rich layers that act as in situ solid lubricant s in the former case. The increase in applied loading fractured FeCrp parti culates, and the wear rates of the composites increased to levels comparabl e to those of unreinforced matrix alloys. In addition to particle fracture, large strains and strain gradients were generated adjacent to contact surf aces. This led to the subsurface crack growth and delamination. At higher l oads when the contact surface temperature exceeded a critical value a trans ition to severe wear observed. It should be considered that the transition loads (and temperatures) were higher in the composites. At the same time, t he composites having higher volume fraction of reinforcements provided bett er resistance to severe wear. Furthermore, wearing the MMCs against a mulli te counterface, which has a smaller thermal conductivity than a counterface made of steel, led to the occurrence of severe wear at lower loads. (C) 20 01 Elsevier Science B.V. All rights reserved.