In-situ investigation of dwell fatigue damage mechanism of pure Ti using digital image correlation technique

〈112̄0〉-orientation-dependent crack initiation in a titanium alloy under dwell fatigue

“…44 Meanwhile, a strong strain rate sensitivity can increase the stress redistribution from soft grains to hard grains caused by the load shedding, thereby increasing the local stress of hard grains and promoting the cracking of hard grains. 37,45 The above results 37,44,45 considering time-dependent deformation show that the soft grain with a large γ angle is more likely to cause the cracking of the adjacent hard grain, which is consistent with the results we obtained based on the calculated stress component. Furthermore, the time-dependent deformation behavior is related to the φ angle in addition to the γ angle.…”

“…In addition, two types of dislocations are formed in crystals during deformation, namely GND and statistically stored dislocation. 33,34 The hard grain is poorly oriented for slips (low basal and prismatic slip Schmid factors), resulting in little plastic deformation [35][36][37] and thus low statistically stored dislocation density during dwell fatigue. Therefore, the GND density has been mainly determined and discussed in this paper.…”

“…37,[41][42][43][44][45] Numerous investigations show that the time-dependent deformation behavior (or strain rate sensitivity) of a grains is closely relevant to their crystallographic orientation. 37,43,44 The strain rate sensitivity of a grains varies with the declination angle (g angle) between their c-axis and the applied stress, with a larger g angle associated with stronger strain rate sensitivity. 44 Meanwhile, a strong strain rate sensitivity can increase the stress redistribution from soft grains to hard grains caused by the load shedding, thereby increasing the local stress of hard grains and promoting the cracking of hard grains.…”

“…Moreover, the time-dependent deformation of a grains also affects the initiation of dwell fatigue cracks. 37,[41][42][43][44][45] Numerous investigations show that the time-dependent deformation behavior (or strain rate sensitivity) of a grains is closely relevant to their crystallographic orientation. 37,43,44 The strain rate sensitivity of a grains varies with the declination angle (g angle) between their c-axis and the applied stress, with a larger g angle associated with stronger strain rate sensitivity.…”

A machine learning study on the fatigue crack path of short crack on an α titanium alloy

“…The chemical composition is shown in table 1. Numerous studies have demonstrated that suitable heat treatment conditions can result in an increase in grain size for TA2 [30]. In this study, the fabricated materials were subjected to a heat treatment process at 830°C for 24 h to achieve a relatively large coarse-grained structure, which facilitates subsequent experiments.…”