Effect of stress ratio on fatigue crack growth of Ti40 alloy
(1. Titanium Research Center, Northwest Institute for Non-ferrous Metal Research, Xi’an 710016, China;
2. School of Materials Science and Engineering, Northwestern Polytechnical University,
Xi’an 710072, China)
2. School of Materials Science and Engineering, Northwestern Polytechnical University,
Xi’an 710072, China)
Abstract: The effect of stress ratio on fatigue crack growth (FCG) behavior of Ti40 alloy was analyzed. A unified approach, developed by VASUDEVAN and SADANANDA was used. The approach is based on the realization that fatigue requires two load parameters for unambiguous description. They are two fracture mechanics parameters: the maximum stress intensity factor Kmax and the stress intensity amplitude ΔK. The results show that there are two mechanisms controlling the FCG behavior of Ti40 alloy. The curves of the two mechanisms in trajectory map are similar. They deviate to Kmax axial more strongly compared with other titanium alloy, which indicates that Ti40 alloy is more sensitive to environment.
Key words: Ti40 alloy; stress-ratio; fatigue crack growth; unified approach; trajectory map