【摘要】 利用腐蚀疲劳测试系统研究了高温高压水环境下两种压水堆核电站一回路主管道用不锈钢的腐蚀疲劳裂纹萌生行为。结果表明,316LN奥氏体不锈钢的裂纹主要在材料表面的驻留滑移带处萌生,少量裂纹在两簇驻留滑移带交界的亚晶界面处。含有少量铁素体的Z3CN20.09M奥氏体不锈钢的疲劳裂纹依次在试样表面的驻留滑移带处、相界处和点蚀坑处萌生,但主要是在驻留滑移带处。通过研究高温高压水环境下氧化膜的组成和腐蚀疲劳试样横截面的形貌,分析了疲劳裂纹在滑移带处萌生的机理。最后对比分析两种不锈钢裂纹萌生机制的异同,并讨论了铁素体对材料腐蚀疲劳性能的影响。更多还原

【Abstract】 The behaviors of fatigue crack initiation of 316 LN and Z3 CN20.09 Maustenite stainless steels(ASSs)were studied by corrosion fatigue test system in high temperature water.The results indicated that the fatigue cracks were mainly initiated at the persistent slip bands(PSBs)on the surface of 316 LN ASS.Only a few cracks were initiated at the sub-grain boundaries.While the fatigue cracks were sequentially initiated at PSBs,phase boundaries and corrosion pits of the Z3 CN20.09 M ASS containing a little part of ferrite,and they were also mainly initiated at PSBs.The crack initiation mechanism at PSBs was analyzed based on composition of oxide film and morphology of cross section of the specimens tested in high temperature water.Moreover,the difference of the crack initiation mechanisms for two kinds of stainless steel was analyzed.Finally,the effect of the ferrite phase on corrosion fatigue property was summarized.更多还原