Dwell fatigue and cycle deformation of CP-Ti at ambient temperature

Abstract

The influences of stress and hold time on cycle deformation and failure life of CP-Ti dwell fatigue were systematically investigated. Two dwell fatigue regions were divided by dwell fatigue parameters. At high stress region, creep and ratcheting behaviors are significant, and the failure mechanism is the ductile fracture caused by large deformation. But at low stress region, creep and ratcheting behaviors are tempered, and the failure mechanism is the classical fatigue fracture. It is worth noting that, the influences of hold time on dwell fatigue parameters are different at different dwell fatigue regions. Moreover, the creep and ratcheting interaction was discussed, and the dwell fatigue strain changes from ratcheting strain controlled to creep strain controlled with hold time increasing. At last, since the dwell fatigue life debits are different at different dwell fatigue regions, the dwell fatigue life prediction model considering fatigue, creep and ratcheting was proposed for the dwell fatigue behavior of CP-Ti at ambient temperature.