Observation of fretting fatigue cracks of Ti6Al4V titanium alloy

Using a test system developed in laboratory, the fretting fatigue mechanism of Ti6Al4V alloy has been studied, with analyses of fracture morphology and composition. The results show that fretting fatigue source area is semi-elliptical and occupies a small proportion of the total fracture surface. The area is relatively flat and smooth and shows traces of friction. With the increase of contact pressure, the depth of the source region first increases rapidly and then stabilizes, but the fatigue strength decreases rapidly and then stabilizes. Fretting causes severe oxidation of the surface. In the interface between the source and the fatigue propagation zone, the contents of O and Fe drop sharply.