文献类型：期刊文献

英文题名：Microstructural Evolution along the NiCrMoV Steel Welded Joints Induced by Low-Cycle Fatigue Damage

作者：Weng, Shuo[1,2,3];Huang, Yuhui[4];Zhu, Mingliang[4];Xuan, Fuzhen[4]

机构：[1]Univ Shanghai Sci & Technol, Sch Mech Engn, Shanghai 200093, Peoples R China;[2]Univ Shanghai Sci & Technol, Machinery Ind Key Lab Mech Strength & Reliabil Ev, Shanghai 200093, Peoples R China;[3]Shanghai Technol Serv Platform Reliabil Evaluat N, Shanghai 200093, Peoples R China;[4]East China Univ Sci & Technol, Sch Mech & Power Engn, Shanghai 200237, Peoples R China

年份：2021

卷号：11

期号：5

外文期刊名：METALS

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000662584700001)】；

基金：The work was sponsored by the National Natural Science Foundation of China (Grant No. 51875202 and 52005336), Shanghai Sailing Program (19YF1434400) and China Postdoctoral Science Foundation (2020M671167).

语种：英文

外文关键词：microstructure; fatigue; dislocations; strength; transmission electron microscopy (TEM)

摘要：The degradation of mechanical properties of materials is essentially related to microstructural changes under service loadings, while the inhomogeneous degradation behaviors along welded joints are not well understood. In the present work, microstructural evolution under low-cycle fatigue in base metal (BM) and weld metal (WM) of NiCrMoV steel welded joints were investigated by miniature tensile tests and microstructural observations. Results showed that both the yield strength and ultimate tensile strength of the BM and WM decreased after low-cycle fatigue tests, which were attributed to the reduction of dislocation density and formation of low-energy structures. However, the microstructural evolution mechanisms in BM and WM under the same cyclic loadings were different, i.e., the decrease of dislocation density in BM was attributed to the dislocation pile-ups along the grain boundaries, dislocation tangles around the carbides at the lower strain amplitudes (+/- 0.3% or +/- 0.5%). Additionally, when the strain amplitude was +/- 8%, the dislocation density was further decreased by the formation of subgrains in BM. For WM, the dislocation density decreased with the increase of strain amplitude, which was mainly caused by the dislocation pile-ups along the grain boundaries and the formation of subgrains.