Fretting fatigue behaviour of Ti–6Al–4V alloy under plane bending stress and contact stress

Fretting fatigue tests for Ti–6Al–4 V alloy were conducted by use of the plate fatigue specimen with bolt-tightened shoe on both sides of the plate. It was clarified that the repeated bending stress at the contact area where fretting fatigue failure starts linearly decreased as stress over the contact area increased. Fretting fatigue crack starts from the pit where stress concentrate. The pit initiates when fretting debris were removed from the surface striation formed due to the contact slip movement. The fretting fatigue crack initiation mode was transgranular, while the fretting fatigue crack propagation mode was striation.