Influence of soft interlayers on fretting fatigue and fretting wear resistance of Ti-6Al-4V alloy

Abstract

Ti-6Al-4V alloy is the main structure material of aerospace components due to its excellent corrosion resistance, high specific strength and other good characteristics. However, this alloy has low hardness, poor wear resistance and higher friction coefficient, so it is very sensitive to fretting wear (FW) and fretting fatigue (FF) damages. In this work, we studied three kinds of soft inter-layers (copper foil, nickel foil and polytetrafluoroethylene (PTFE) lamella) between the Ti-6Al-4V fatigue samples and the Ti-6Al-4V counterparts respectively to enhance the FF and FW resistance of this alloy. The results show that the method is an economical and effective way to increase the FF and FW resistance of Ti-6Al-4V alloy. The order of enhancement in the FF resistance of the titanium alloy was copper foil > PTFE lamella > nickel foil. Additionally, the friction coefficients of PTFE lamella, copper foil, nickel foil and Ti-6Al-4V alloy were about 0.10, 0.60, 0.65 and 1.1, respectively. The lowest friction coefficient of PTFE, compared with copper foil, nickel foil and substrate, was of great benefit to improving the FF property of Ti-6Al-4V alloy. Nevertheless, the FF life of Ti-6Al-4V alloy with the copper interlayer was higher than PTFE, which was about 5 times higher than substrate.