摘要
17-4沉淀硬化马氏体不锈钢阀杆广泛应用于压水堆核电站中,该阀杆在高温(300～350℃)下长期服役时面临热老化脆化问题,影响核电站安全。本文针对核电站实际服役的阀杆样品,开展了小角中子散射实验,结合冲击试验、扫描电子显微镜和金相显微镜分析等,将严重老化与轻微老化的阀杆样品进行对比,研究了试样在长期热时效过程中内部nm结构的变化。冲击试验、断口的扫描电镜和金相组织图像显示,严重老化的阀杆发生了明显的脆化现象。利用多分散小球模型和Porod定律对小角中子散射实验数据进行拟合,结果表明,球形nm析出物直径约为1nm,随着热老化程度的加剧,nm析出物尺寸变大,体积分数增多约19%。小角中子散射结果与材料的宏观力学性能变化有明显的关联性。
17-4 precipitation hardening（PH）stainless steel valve rods are widely used in PWR power plants.When 17-4 PH valve rod has been working under high temperature（around 300-350 ℃）for a long time,it will face the problem of embrittlement due to thermal aging and affect the safety of the nuclear power plant.Small angle neutron scat-tering（SANS）experiment for real valve rod used in nuclear power plants was conducted.Combined with other methods including Charpy impact test,scanning electron microscope and metallographic microscope,differences between severely aging and slightly aging valve rod samples from nuclear power plants were compared,and changes in nanostructure inside the material during long-term thermal aging were studied.From changes in impact energy and scanning images,brittle of severely aging valve rod can be seen clearly.Polydisperse sphere model and Porod law were used for fitting in SANS analysis.The results show that nano precipitates are basically sphere around 1 nm in diameter.In the process of thermal aging,the size grows and the volume fraction increases about 19%.The result of SANS is clearly correlated to changes in macroscopic mechanical properties.
作者
张佩佩
李天富
白冰
佟振峰
王子军
刘蕴韬
ZHANG Peipei;LI Tianfu;BAI Bing;TONG Zhenfeng;WANG Zijun;LIU Yuntao(Department of Nuclear Physics,China Institute of Atomic Energy,Beijing 102413,China;Division of Reactor Engineering Technology Research,China Institute of Atomic Energy,Beijing 102413,China;Division of Radiation Metrology,China Institute of Atomic Energy,Beijing 102413,China)
出处
《原子能科学技术》
EI
CAS
CSCD
北大核心
2018年第12期2283-2288,共6页
Atomic Energy Science and Technology
基金
国家自然科学基金资助项目(11575295)
关键词
小角中子散射
17-4沉淀硬化不锈钢
阀杆
nm结构
small angle neutron scattering
17-4 precipitation hardening stainless steel
valve rod
nanostructure
