Fretting fatigue behaviors of Ti811 alloy at elevated temperature

The fretting fatigue (FF) behaviors of Ti811 alloy influenced by temperature, slip amplitude and contact pressure were investigated using high frequency fatigue machine and self-made high temperature apparatus. The FF mechanisms were discussed by observing fretting surface morphology features. The results show that FF sensitivity is high at both 350°C and 500°. The higher the temperature is, the more sensitive the FF failure of the alloy. Creep is the important factor which influences FF failure process of Ti811 alloy at elevated temperature. The FF life of the alloy doesn't change in a monotone way with the increasing slip amplitude and contact pressure. This is due to the fact that slip amplitude affects the action of fatigue and wear in fretting process, the nominal contact pressure affects the distribution and concentration of stress and fretting slip amplitude value at contact surface, further influences crack initiation probability and propagation driving force.