核电压力容器600合金小裂纹应力腐蚀开裂扩展速率的定量预测（英文）  

Quantitative Prediction of Stress Corrosion Crack Propagation Rate of Small Crack in Alloy 600 for Nuclear Pressure Vessels

作　　者：方秀荣[1] 杨锦辉 邵艳茹 欧雪 Fang Xiurong;Yang Jinhui;Shao Yanru;Ou Xue(Xi'an University of Science & Technology,Xi'an 710054,China)

机构地区：[1]西安科技大学

出　　处：《稀有金属材料与工程》2019年第8期2424-2431,共8页Rare Metal Materials and Engineering

基　　金：National Natural Science Foundation of China(51775427)

摘　　要：小裂纹应力腐蚀开裂(SCC)在核电关键构件(NPPs)的全寿命衰减过程有重要影响。通过将薄膜滑移-溶解/氧化模型与弹塑性有限元(EPFEM)相结合,定量预测核电反应堆压力容器(RPV)中小裂纹SCC扩展速率。根据裂纹尖端力学场的分析,确定以裂纹尖端应变率来表征小裂纹的萌生和扩展,并通过距离扩展小裂纹尖端特定的r0处的塑性应变(dep/da)来近似表征裂纹尖端应变率。提出了基于弹塑性断裂力学的动态裂纹扩展和准静态裂纹扩展2种方法计算塑性应变(dep/da),并进行2种计算方法比对塑性应变随裂纹长度变化的敏感性,得到2种计算方法之间差异的同时,也确定小裂纹扩展的塑性应变变化比长裂纹更为敏感。小裂纹的SCC扩展速率大于长裂纹的SCC扩展速率,距裂尖的特征距离r0是重要的影响因子,鉴于特定距离r0难以确定,建议通过将相同环境和相同材料下的SCC实验数据结合单边拉伸试样的有限元数值计算结果来确定。研究结果能够实现核电关键结构材料的SCC扩展速率定量预测及服役压力容器的安全评价。Stress corrosion crack(SCC) of small crack has an important effect on the whole-life attenuation process of critical structures in nuclear power plants(NPPs). By combining the film slip-dissolution/oxidation model with the elastic-plastic finite element method(EPFEM), the SCC propagation rate for small crack in reactor pressure vessels(RPVs) of NPPs was quantitatively predicted. According to the crack tip mechanical field analysis, the crack tip strain rate was determined to control the initiation and propagation of small cracks, and it was approximately calculated by the variation of plastic strain(dep/da) at a characteristic distance r0 to the growing small crack tip. Two methods of dynamic crack propagation and quasi-static crack propagation based on EPFEM were proposed to calculate the variation of plastic strain(dep/da). The contrast of the two calculation methods and the sensitivity analysis of variation of plastic strain with the crack length were carried out. The results show that there is a slight difference between the two methods, and the plastic strain variation is more sensitive to the crack propagation of small crack than to the long crack. The SCC propagation rate of small cracks is larger than that of long cracks, and it is significantly influenced by the characteristic distance r0. As it is difficult to determine the value of characteristic distance r0 finally, it is suggested to be determined by combining experimental SCC data with finite element simulation of the single-edge crack panel specimens under the same environmental and material conditions.

关 键 词：600合金 应力腐蚀裂纹 定量预测 裂纹尖端应变 弹塑性有限元法 

分 类 号：TG172[金属学及工艺—金属表面处理] TM623[金属学及工艺—金属学]