Fatigue Crack Propagation of TC4ELI Titanium Alloy： Path Deflection and Life Enhancement Mechanism

doi:10.3901/JME.2023.16.072

Abstract

Abstract: As the optimal material for deep-sea manned equipment structure, TC4ELI(Extra-low-interstitial) titanium alloy's anti fatigue crack growth performance is crucial. In this work, the fatigue crack growth behavior of TC4ELI is systematically tested and observed in situ, and the traditional TC4 titanium alloy is selected for comparative experiments. The results show that TC4ELI has a higher fatigue crack growth life than TC4; At the same time, in situ observation found that the fatigue crack growth of TC4ELI is obviously deflected, resulting in a more tortuous crack path than TC4. Furthermore, TC4ELI fatigue fracture surface, material composition and microstructure of crack path region were systematically analyzed by means of microscopic characterization. On this basis, the variation of crack growth driving force with deflection angle is calculated by finite element simulation, and the influence mechanism of crack deflection on TC4ELI fatigue growth life is analyzed. This study provides a reference for the damage tolerance design of TC4ELI deep-sea equipment structure.

Key words: TC4ELI titanium alloy, deep-sea equipment, fatigue crack, path deflection, life enhancement

CLC Number:

TH114

YU Peishi, ZHAO Yuxiang, WU Liansheng, BIAN Jiakun, ZHAO Junhua, GUO Wanlin. Fatigue Crack Propagation of TC4ELI Titanium Alloy： Path Deflection and Life Enhancement Mechanism[J]. Journal of Mechanical Engineering, 2023, 59(16): 72-81.

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