In-situ observations on local fracture behavior in a dissimilar metal weld joint of nuclear power plant
In this paper, the local fracture behavior in notched specimens made from a real nuclear dissimilar metal welded joint (DMWJ) of nuclear power plant (NPP) were investigated and analyzed by using in-situ tensile tests via scanning electron microscope (SEM). The results show that the cracks in specimens firstly initiate at the notch tips at the maximum loads, and then propagate in a way of step by step with increasing the tensile displacement and decrease of the load. The fracture is dominated by ductile void fracture mechanism. The cracks in the specimens with inhomogeneous material generally initiate and propagate in the materials with lower yield stress. There is great difference in the load-carrying capacity and fracture toughness for the specimens with different initial crack locations in the DMWJ. This is caused by the local mechanical properties, the local strength mismatch and crack growth resistance of the material ahead of notches. The specimens with local higher yield stress, local strength overmatch and higher crack growth resistance of the material ahead of notches have higher loadcarrying capacity and fracture toughness. While for the specimens with local lower yield stress, local strength undermatch and lower crack growth resistance of the material ahead of notches, there are lower fracture toughness and local brittle crack growth. For assessing the integrity of the DMWJ accurately, the local mechanical properties and their local mismatches ahead of defect tips should be considered, and the new method based on local damage and fracture mechanics needs to be developed.
Local fracture behavior Dissimilar metal welded joint In-situ observation Mismatch Nuclear power
Haitao Wang Guozhen Wang Fu-Zhen Xuan Changjun Liu Shan-Tung Tu
Key Laboratory of Pressure Systems and Safety, Ministry of Education, School of Mechanical and Power Engineering, East China University of Science and Technology, Shanghai 200237, China
国际会议
2011 International Symposium on Structural Integrity 2011国际结构完整性学术研讨会--核工程结构完整性技术 ISSI 2011
合肥
英文
64-72
2011-10-27（万方平台首次上网日期，不代表论文的发表时间）