Fretting fatigue behavior of Ti-6Al-4V at elevated temperature

Fretting fatigue behavior of titanium alloy, Ti-6Al-4V at elevated temperature of 260 °C was investigated by conducting experiments and finite element analysis. The static coefficient of friction (COF) increased slightly during the early stage of fretting cycling and then remained constant throughout the rest of the life. The values of COF and its dependence on fretting cycling at 260 °C were almost similar to those at room temperature. This similar behavior of COF at room temperature and 260 °C resulted from the fact that the glaze oxide layers did not form on the Ti-6Al-4V surface at 260 °C. The reductions in fatigue life and fatigue strength due to fretting from their counterparts in plain fatigue were significant at 260 °C as well as at room temperature. However, there was practically no difference between room temperature and 260 °C life data either in the plain fatigue or fretting fatigue condition. A critical plane-based model, modified shear stress range parameter, was found to be effective to correlate the lives from the fretting and plain fatigue at both room and elevated temperatures. Also, it predicted the location of fretting fatigue crack initiation and its orientation which were in agreement with their experimental counterparts.