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裂纹尖端氧化膜形成与破裂是核电站压力容器高温水环境中镍基合金材料应力腐蚀开裂(SCC)的主要过程之一。由于应力腐蚀裂纹尖端形貌和扩展方式的特殊性,本研究利用ABAQUS有限元软件的子模型技术,在微观尺度下对由裂尖氧化膜和基体金属共同构成的应力腐蚀裂尖应力应变场进行了分析。结果表明,SCC裂尖氧化膜前端沟形裂纹的存在,会造成氧化膜中应力和应变的很大变化,且随着沟形裂纹的长度增加,这种变化越加明显;另一方面,与氧化膜中应力相比,塑性应变对裂尖形貌变化更加敏感,从一个侧面说明,裂尖塑性应变是研究SCC裂尖氧化膜形成与破裂比较理想的力学参量。
Crack tip oxide film formation and rupture is one of the main processes of stress corrosion cracking (SCC) of nickel base alloy materials in high temperature water environment of nuclear power station pressure vessel. Due to the peculiarities of stress corrosion crack tip morphology and extension mode, this study uses the ABAQUS finite element software submodeling technique to simulate the stress and strain field of stress corrosion cracking tip composed of crack tip oxide film and base metal microscopically Analysis. The results show that the presence of grooved cracks at the tip of SCC crack tip leads to large changes of stress and strain in the oxide film, and this change becomes more obvious as the length of groove crack increases. On the other hand, Compared with the stress in the oxide film, the plastic strain is more sensitive to the morphological changes of the crack tip. From one side, the plastic strain at the crack tip is the ideal mechanical parameter for studying the formation and fracture of the crack tip oxide film on the SCC.