摘要
全球迄今发生的核电安全事件往往是由局部腐蚀造成,而局部腐蚀从表面起始。表面状态如何影响腐蚀,以及辐照和应力与之的交互作用已经成为核电站运行安全性、可靠性、经济性保障的重要技术难题之一。本文系统总结了在过去十余年的国家系列项目支持下,针对核电用关键结构材料在不同表面加工与划伤后微观组织变化、在模拟核电站一回路水中的腐蚀、应力腐蚀和辐照促进应力腐蚀行为,并将这些腐蚀行为与材料的微观组织以及力学、辐照等多因素相关联。结果表明,打磨、划伤和切削加工都会使材料近表面产生不同程度的梯度结构,表面变形层状态存在较大差异。划伤后,在划伤底部存在大于屈服极限的残余压应力。相同粗糙度的切削加工表面,机加工参数不同可以导致深度方向上形成的纳米晶区、晶粒畸变区梯度结构明显不同。这种微观组织与局部应力应变条件使得材料抗腐蚀能力差异显著,例如划伤导致的应力腐蚀裂纹数量与划伤深度正相关。在辐照、腐蚀、应力的联合作用下,辐照促进应力腐蚀敏感性进一步升高。最后展望了未来发展趋势。
Global nuclear power events are often caused by local corrosion,which starts at the surface.The effect of the surface state on corrosion and the interaction among corrosion,irradiation,and stress are important technical problems affecting the safety,reliability,and economy of nuclear power plants.In this paper,supported by a series of national projects in the last 10 years,the various surface state effects,for key structural materials used in nuclear power plants after surface finishing,grinding,machining,or scratching,on corrosion and stress corrosion behaviors in the simulated primary water of nuclear power plants are reviewed.The results show that surface grinding,scratching,or cutting can cause the formation of microstructures of different gradients near the surface and also cause large differences in surface deformation.For example,the residual compressive stress is greater than the yield stress in the superficial surface of the scratch;the different cutting parameters can cause the various gradient structures of the nanocrystalline and grain distortion zones to form along the depth of the cutting surface with similar surface roughness.Such microstructures and local stress-strain conditions lead to significant differences in corrosion resistance.For example,the number of stress corrosion cracks is positively correlated with scratch depth.Under the combined action of irradiation,corrosion,and stress,irradiation-assisted stress corrosion is further enhanced.Finally,the future research trend on the topic is forecast.
作者
韩恩厚
王俭秋
HAN En-Hou;WANG Jianqiu(CAS Key Laboratory of Nuclear Materials and Safety Assessment,Institute of Metal Research,Chinese Academy of Sciences,Shenyang 110016,China;Institute of Corrosion Science and Technology,Guangzhou 510535,China;School of Materials Science and Engineering,South China University of Technology,Guangzhou 511442,China)
出处
《金属学报》
SCIE
EI
CAS
CSCD
北大核心
2023年第4期513-522,共10页
Acta Metallurgica Sinica
基金
国家重点基础研究发展计划项目Nos.2011CB610500和2006CB610500
国家重大科技专项项目No.2011ZX06004-009
国家重点研发计划项目No.2016YFE0105200
中国科学院重点部署项目No.ZDRW-CN-2017-1
中国科学院前沿科学重点研究计划项目No.QYZDY-SSW-JSC012。
关键词
表面状态
腐蚀
应力腐蚀
辐照促进应力腐蚀
核电材料
不锈钢
镍基合金
surface state
corrosion
stress corrosion
irradiation-assisted stress corrosion
nuclear material
stainless steel
nickel-based alloy
