Impact of contact size and complex gross–partial slip conditions on Ti–6Al–4V/Ti–6Al–4V fretting wear

The present investigation focuses on the fretting wear kinetics of a Ti–6Al–4V/Ti–6Al–4V interface. The impact of contact size, contact geometry, variable gross slip sliding conditions and combined partial and gross slip sequences are studied. It is shown that for an adhesive wear tribosystem, the wear rate is better captured by coupling debris formation and debris ejection descriptions. Hence a “unified energy wear approach” is derived, providing a stable prediction of wear rates over a large spectrum of pressure, test duration and sliding amplitudes for constant and variable gross slip sliding conditions. By changing the contact size and geometry it is shown that the larger the contact dimension, the lower the energy wear rate. An extended energy wear concept, based on an asymptotic formulation is introduced, enabling macro, meso and micro contact configurations to be correlated. Combined partial slip/gross slip sequences are finally investigated to evaluate the stability of the energy wear formulation. The partial slip sequence is shown to promote fatigue degradation of the third body layer generated during the gross slip period. An incremental formulation integrating the contribution of partial slip fatigue damage of third body is derived.