文献类型：期刊文献

英文题名：Strain visualization of growing short fatigue cracks in the heat-affected zone of a Ni-Cr-Mo-V steel welded joint: Intergranular cracking and crack closure

作者：Liu, Shi-Dong[1];Zhu, Ming-Liang[1,2];Zhou, Hai-Bo[2];Wan, Di[3];Xuan, Fu-Zhen[1]

机构：[1]East China Univ Sci & Technol, Sch Mech & Power Engn, Minist Educ, Key Lab Pressure Syst & Safety, Shanghai 200237, Peoples R China;[2]Cent S Univ, State Key Lab High Performance Complex Mfg, Changsha 12570, Hunan, Peoples R China;[3]Norwegian Univ Sci & Technol, Dept Mech & Ind Engn, Richard Birkelands Vei 2B, N-7491 Trondheim, Norway

年份：2019

卷号：178

外文期刊名：INTERNATIONAL JOURNAL OF PRESSURE VESSELS AND PIPING

收录：;EI(收录号：20194607698748);WOS:【SCI-EXPANDED(收录号:WOS:000501396700007)】；

基金：The authors are grateful for the supports provided by the National Natural Science Foundation of China (51575182, 51835003), and the Open Research Fund of Key Laboratory of High Performance Complex Manufacturing, Central South University (KfIct2016-13).

语种：英文

外文关键词：Short fatigue crack; Crack closure; Crack deflection; Intergranular cracking; Digital image correlation; Strain localization

摘要：Physically short fatigue crack growth behavior in the heat-affected zone of a Ni-Cr-Mo-V steel welded joint was investigated in-situ in SEM to reveal effects of crack closure and tortuous crack growth path on crack-tip straining behavior with the help of high resolution digital image correlation technique. The crack growth path and associated fatigue damage at microstructural scale was characterized by electron backscatter diffraction and electron channeling contrast imaging techniques. Results showed that the short crack growth was influenced by both local microstructure and global strength gradient. The short crack could deflect intergranularly when meeting with one large grain due to misfit deformation and strain localization. The crack closure, which was accompanied during loading and unloading in terms of crack surface contact, shielded the real crack-tip and manifested itself well in both compressive strain at crack wake and strain development at crack-tip. It is indicated that strain localization at lathy boundaries and formation of sub-grains was responsible for the fatigue of short cracks.