Using a high frequency push-pull fatigue testing machine with fretting
pad pressed onto specimen to simulate fretting condition, the
relationship between microstructures, mechanical and fretting fatigue
properties of three different titanium alloys were studied
systematically. Their microstructure, mechanical properties, plain
fatigue and fretting fatigue behaviors were discussed contrastively
through the analysis of the fracture morphology, fatigue source region
and microhardness near the fracture zone. The results show that,
material properties of Ti1023 and Ti55531 are better than that of
Ti6Al4V titanium alloy, but Ti6Al4V titanium alloy shows the best
fretting fatigue performance. For three titanium alloys, with the
increase of the contact stress, the fretting fatigue strength first
decreases and then tends to be stable and the depth of fretting fatigue
source first increases and then tends to be stable. The contact pressure
plays a dual role in the fretting process. Contact pressure promotes
crack initiation and inhibits crack growth. The cyclic loading is the
main inducement for the initiation of plain fatigue microcracks. The
accumulation of plastic deformation is the main cause of microcracks
initiation in fretting fatigue.