Abstract:

Effects of the temperature, slip amplitude, and contact pressure on fretting fatigue (FF) behavior of the Ti811　 titanium alloy were investigated using a high frequency fatigue machine and a home-made high temperature apparatus. The fretting　 fatigue failure mechanism was studied by observing the fretting surface morphology features. The results show that the sensitivity to fretting fatigue is high at both 350 and 500℃. The higher the temperature, the more sensitive to the fretting fatigue　 failure is. Creep is an important factor that influences the fretting fatigue failure process at elevated temperatures. The　 fretting fatigue life of the Ti811 alloy does not change in a monotonic way as the slip amplitude and contact pressure increase.　 This is owing to the fact that the slip amplitude affects the action of fatigue and wear in the fretting process, and the nominal contact　 pressure affects the distribution and concentration of the stress and the amplitude of fretting slip at the contact surface, and thus　 further influences the crack initiation probability and the driving force for propagation.

Key words: Fretting fatigue (FF), Elevated temperature, Titanium alloy, Slip amplitude, Creep