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研究了温度对核电用Z3CN20-09M不锈钢在含Cl的高温高压水中的应力腐蚀开裂行为的影响.材料的应力腐蚀开裂敏感性变化趋势与试验温度变化趋势并不一致.320℃时材料的应力腐蚀开裂敏感性最高,290℃时为最低,250℃时开裂敏感性介于两者之间.250℃和320℃条件下腐蚀后试样表面形成了内部致密、外部疏松的双层氧化膜,而在290℃条件下腐蚀后试样形成的是致密的单层氧化膜.大多数点蚀坑产生于铁素体相.应力腐蚀裂纹优先在点蚀坑底部或相界面形核,并倾向于沿相界面或向铁素体内部扩展.铁素体/奥氏体界面对应力腐蚀裂纹的作用取决于裂纹面与相界面的取向关系.当裂纹扩展方向平行于相界面时,裂纹易沿着相界扩展;当裂纹扩展方向垂直于相界面时,相界面对裂纹扩展起阻碍作用.
The effect of temperature on the stress corrosion cracking behavior of Z3CN20-09M stainless steel in nuclear reactor with high temperature and high pressure water containing Cl was investigated.The tendency of the stress corrosion cracking susceptibility of the material did not change with the change of the test temperature.The stress corrosion cracking The sensitivity is the highest, the lowest is at 290 ℃, the cracking sensitivity is between the two at 250 ℃ .At the same time, the double-layer oxide film with dense internal and external looseness formed on the surface of the samples after corrosion at 250 ℃ and 320 ℃, At 290 ℃, the samples formed a dense monolayer after corrosion.The most pitting corrosion occurred in the ferrite phase.The stress corrosion cracking preferentially nucleated at the bottom or phase interface of pits, Interface or to the ferrite internal expansion of ferrite / austenite interface on the role of stress corrosion cracking depends on the crack surface and phase interface orientation.When the crack propagation direction parallel to the phase interface, the crack along the phase boundary When the crack propagation direction is perpendicular to the phase interface, the phase interface hinders the crack propagation.