Effect of ceramic conversion surface treatment on fatigue properties of Ti6Al4V alloy

Samples of Ti6Al4V alloy were ceramic conversion (CC) treated. The fatigue properties of untreated and CC treated samples were evaluated with a conventional Wöhler cantilever rotating-bending fatigue machine under both plain fatigue and fretting fatigue conditions. Experiment results showed that CC treatment had a detrimental effect on plain fatigue properties and reduced the plain fatigue limit of the investigated Ti6Al4V alloy by about 24%. However, the fatigue property loss could be fully recovered by an additional shot peening after CC treatment. More importantly, shot peening after CC treatment resulted in considerably longer fatigue life over untreated and CC treated materials in the finite-life region. In contrast to its detrimental effect on plain fatigue, CC treatment appeared to be beneficial to fretting fatigue property. It increased fretting fatigue strength (FFS at 107 cycles) of the Ti6Al4V alloy by approximately 10%. Shot peening after CC treatment further enhanced the fretting fatigue properties, with an improvement in FFS (107 cycles) of about 20% over the untreated material under the present treatment and testing conditions.