Abstract:

The effects of the various parameters on the fretting fatigue life and the fretting friction coefficient for a contact pair of titanium alloy and stainless steel are experimentally studied at the room and elevated temperature. The test results show that fretting fatigue life heavily declines at low tensile stresses, and its greatest decrease corresponds to the contact pressure at which the dissipated friction work is the maximum. It changes with temperature nonlinearly:it decreases first when the temperature is between 20 to 200℃, increases up to 300℃ and then reduces to several cycles between 400 to 500℃. The fretting fatigue life under complex loads monotonously decreases with the increase of the high cycle load while the low cycle loads keep constant. The friction coefficient (FC) increases with the number of cycles at the beginning, then reduces, and finally keeps a stable value. FC reduces greatly with the increase of the temperature due to the formation of the lubricious oxide film. FC increases linearly with the amplitude when it is less than the critical value and then keeps constant, the value of the coefficient can be regressed as f=2.691-0.409 ln_N^e. The coefficient increases from 0.2 to 0.8 with the increase of amplitudes from 5 to 45 micrometers.

Key words: fretting fatigue, complex load, titanium alloy, fretting friction coefficient