Fracture behavior of low cycle fatigue and dwell fatigue ofTC17 titanium alloy under high load

Abstract:

Effect of different loading waveform on fatigue damage of TC17 titanium alloy under the high stress level is researched. The results show that the dwell fatigue life is lower than low cycle fatigue life for TC17 titanium alloy under the peak stress and the dwell loading for 120s. Under the condition of the same high load dwell fatigue, the fatigue sensitivity of lamellar organization is lower than that of the equiaxed structure. Fracture analysis shows that the crack source of dwell fatigue appeared on the surface and sub-surface of the sample, while that of low cycle fatigue appeared on the surface of the sample. The fracture surface of dwell fatigue was flatter than that of the conventional low cycle fatigue, and the fracture mode did not change fundamentally under the dwell loading condition.

Key words:TC17 titanium;alloy,dwell;fatigue,fracture;analysis