Initiation and propagation of small fatigue crack in beta titanium alloy observed through synchrotron radiation multiscale computed tomography
Initiation and propagation of small fatigue crack in beta titanium alloy observed through synchrotron radiation multiscale computed tomography
复制标题
同步辐射多尺度计算机断层扫描观察β钛合金细小疲劳裂纹的萌生和扩展
DOI：
10.1016/j.engfracmech.2022.108308
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发表时间：
2022
影响因子：
5.4
通讯作者：
Uesugi Kentaro
中科院分区：
文献类型：
--
作者：
Xue Gaoge;Nakamura Takashi;Fujimura Nao;Takahashi Kosuke;Oguma Hiroyuki;Takeuchi Akihisa;Uesugi Masayuki;Uesugi Kentaro
同步辐射CT是一种新兴的无损材料断裂分析方法。本文采用显微断层扫描（micro-CT）和纳米断层扫描（nano-CT）相结合的方法对β钛合金Ti-22 V-4Al的原位裂纹扩展进行了监测。利用显微CT技术获得了小裂纹的三维特征和相应的应力强度因子范围（ΔK），裂纹起始于疲劳寿命的10%左右。在低Δ K状态下，裂纹纵横比的分散性和裂纹扩展速率的偏差显著，但随着ΔK的增加而减小，反映了微观结构对小裂纹扩展的影响。通过纳米CT成功地可视化了β钛合金的微观结构。因此，裂纹周围的微观结构的相互作用证明，疲劳裂纹从β晶粒的中心，其中α相是较少沉淀。
Synchrotron radiation computed tomography is an emerging nondestructive method for fracture analysis in materials. Herein, thein situsmall-crack growth of a beta titanium alloy, Ti–22V–4Al, was monitored by a combination of microtomography (micro-CT) and nanotomography (nano-CT). The 3D characteristics of small cracks and the corresponding stress intensity factor range (ΔK) were obtained by micro-CT; the cracks initiated at ∼10% fatigue life. In the low-ΔKregime, the scatter of the crack aspect ratio and the deviation in the crack propagation rate were significant; however, they decreased with increasing ΔK, reflecting the microstructural effect on small-crack propagation. The microstructure of the beta titanium alloy was successfully visualized by nano-CT. Consequently, the crack-surrounding-microstructure interactions evidenced that the fatigue cracks initiated from the center of the beta grain wherein the alpha-phase was less precipitated.