Crack Initiation Mechanism and Life Prediction of Ti60 Titanium Alloy Considering Stress Ratios Effect in Very High Cycle Fatigue Regime

Ruixiang He; Haotian Peng; Fulin Liu; Muhammad Kashif Khan; Yao Chen; Chao He; Chong Wang; Qingyuan Wang; Yongjie Liu

doi:10.3390/ma15082800

Crack Initiation Mechanism and Life Prediction of Ti60 Titanium Alloy Considering Stress Ratios Effect in Very High Cycle Fatigue Regime

Materials (Basel). 2022 Apr 11;15(8):2800. doi: 10.3390/ma15082800.

Authors

Ruixiang He^{1

2}, Haotian Peng^{1

2}, Fulin Liu^{1

2}, Muhammad Kashif Khan³, Yao Chen^{1

2}, Chao He^{1

2}, Chong Wang^{1

2}, Qingyuan Wang^{1

2}, Yongjie Liu^{1

2}

Affiliations

¹ Failure Mechanics and Engineering Disaster Prevention Key Laboratory of Sichuan Province, Sichuan University, Chengdu 610207, China.
² MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu 610065, China.
³ Institute of Future Transport and Cities, Coventry University, Coventry CV1 5FB, UK.

Abstract

Ultrasonic fatigue tests were performed on Ti60 titanium alloy up to a very high cycle fatigue (VHCF) regime at various stress ratios to investigate the characteristics. The S-N curves showed continuous declining trends with fatigue limits of 400, 144 and 130 MPa at 10⁹ cycles corresponding to stress ratios of R = -1, 0.1 and 0.3, respectively. Fatigue cracks found to be initiated from the subsurface of the specimens in the VHCF regime, especially at high stress ratios. Two modified fatigue life prediction models based on fatigue crack initiation mechanisms for Ti60 titanium alloy in the VHCF regime were developed which showed good agreement with the experimental data.

Keywords: Ti60 titanium alloy; fatigue failure mechanism; fatigue life prediction; fatigue strength prediction; stress ratio; very high cycle fatigue.

Abstract

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