氧化膜厚度对应力腐蚀裂纹尖端蠕变的影响

Effect of oxide film thickness on creep at tip of stress corrosion cracking

针对应力腐蚀开裂裂纹尖端的基体金属在高应变条件下发生的蠕变现象,采用有限元软件ABAQUS对高温水环境下合金600含氧化膜的应力腐蚀开裂裂纹尖端的高应力状态进行了数值模拟,并对裂纹尖端的力学场分布规律及氧化膜厚度对基体材料蠕变的影响进行了分析。结果表明:蠕变后,基体金属裂尖应力值减小,应变值会增大;氧化膜越薄,基体金属裂尖区域的蠕变量越大;高蠕变区域主要分布在与裂纹扩展方向线垂直的方向上,裂纹会沿氧化膜破裂方向扩展。本研究为准确预测核电关键结构材料应力腐蚀开裂裂纹的扩展速率奠定了一定的基础。

Aiming at the creep on the base metal in high strain area at the SCC tip,the mechanical state at the SCC tip constituted by the oxide film and Alloy 600 is simulated by using ABAQUS finite element software and the effect of the oxide film thickness on the creep behavior in the base metal is analyzed.The results show that the high stress of crack tip should be released in the process of creep,and the strain value will increase.The thinner oxide film,the greater creep area at the crack tip,and high creep area is mainly distributed in the direction perpendicular the direction of crack propagation,and crack is extended along the direction of film rupture,which provide a foundation to predict SCC growth rate accurately in key structure materials of nuclear power plants.