高温水中应力腐蚀开裂机理及扩展模型-中国材料进展

文章信息/Info

Title:: Mechanisms and Growth Rate Models for Stress Corrosion Cracking in High Temperature Water

作者:: 吕战鹏; （1. 上海大学材料科学与工程学院，上海 200072)
（2. 上海大学省部共建高品质特殊钢冶金与制备国家重点实验室，上海 200444）

Author(s):: LU Zhanpeng; （1. School of Materials Science and Engineering, Shanghai University, Shanghai 200072，China）
（2. State Key Laboratory of Advanced Special Steels, Shanghai University, Shanghai 200444, China)

Keywords:: stress corrosion cracking; nuclear power plant; high temperature water; crack growth rate; oxidation kinetics; crack tip strain rate

摘要:: 核电站结构材料在高温水中应力腐蚀开裂是影响安全运行的重要因素。总结了合金成分、载荷和环境介质等多种因素对奥氏体合金在高温水中应力腐蚀开裂扩展过程的影响规律,简要介绍了几种应力腐蚀开裂机理模型。分析了高温水中的应力腐蚀开裂基元过程，提出了载荷对合金在高温水中界面反应的物理加速作用和物理化学加速作用原理。发展了基于连续介质力学裂纹尖端力学场与氧化动力学相结合的裂纹扩展速率的形变/氧化交互作用理论模型，针对模型中使用的准固态氧化动力学规律以及裂尖渐进场的适用性进行了分析，发现环境温度、材料成分和水化学对氧化动力学的影响与相应条件下奥氏体合金应力腐蚀开裂行为变化特征相对应，裂尖渐进场的适用性也得到了验证。将形变/氧化交互作用模型应用于多种条件下不锈钢和镍基合金在压水堆一回路水中应力腐蚀开裂扩展速率评价，所得模型预测结果与实验室和现场数据结果相一致。

Abstract:: Stress corrosion cracking (SCC) of structural materials in high temperature water in nuclear power plants is one of the important factors for the safety operation. In this paper, the effects of alloy composition, loading and environmental factors on SCC growth of austenitic alloys in high temperature water environments are reviewed. Some available SCC mechanisms are briefly introduced. The element processes involved in SCC are categorized, and the physical degradation and physicalchemical degradation modes due to loading on the interfacial reactions in high temprature water are proposed. The deformation/oxidation interaction model for SCC growth rate is developed, based on the combination of the crack tip continuum mechanics and the oxidation kinetics. The fittness for the adopted oxidation kinetics and the crack tip asymptotic field in the SCC growth rate model is checked. It is found that the effects of temperature, material composition and water chemistry on oxidation kinetics correspond well to their effects on SCC growth rate. The compatibility of the adopted crack tip mechanical field is also confirmed. The calculated results with the developed SCC growth rate model based on deformation/oxidation interaction are found to be consistent with the reported experimental SCC growth rates and plant data.