Abstract
Abstract
In this study, friction and wear tests were conducted on a TiAl alloy and a nickel-based powder metallurgy (P/M) superalloy. The test results were analyzed and compared to elucidate the friction and wear mechanisms of the two materials and to validate the proposed wear model. These findings indicate that high-hardness oxidized composite debris accumulates on the contact surface. In the early stage, ploughing predominates, leading to an accelerated wear rate. As friction progresses, the accumulation of debris and the formation of a hardened layer partially mitigate the wear rate. However, prolonged friction causes fragmentation of the debris layer, and the subsequent interaction between the hardened debris and the surface promotes additional ploughing, thereby increasing the wear rate once more. This study developed an energy-based wear model that accounts for the observed reduction in the coefficient of friction (COF) with increasing normal load and sliding frequency. The discrepancy between the fitted and experimentally measured friction coefficients is within 20%. Simulations based on this model produced wear depth predictions within a 5 μm margin of error relative to experimental measurements, thereby demonstrating high predictive accuracy.