316LN不锈钢在高温高压水环境下的腐蚀疲劳行为研究

在室温纯水、高温纯水及高温硼锂水环境下开展了316LN不锈钢在不同应变幅加载下的腐蚀实验研究，并获得了3种条件下的腐蚀疲劳寿命曲线。结果表明，316LN不锈钢在加载过程中出现了先硬化后软化现象，且随循环周次增加，应力峰值逐渐下降；高温纯水及高温硼锂水环境下材料的腐蚀疲劳性能下降，加速了材料的腐蚀疲劳失效；在高应变幅条件下高温的软化作用占主要影响，低应变幅条件下腐蚀作用占主要影响；试验后的样品断面上均可观察到疲劳辉纹、滑移变形带及二次裂纹，高温水腐蚀环境会加速裂纹扩展，加速疲劳失效。 

Investigation on Corrosion Fatigue Behavior of 316LN SS under High Temperature Water Environment

Corrosion fatigue behavior of SS316 LN was investigated in high temperature water environment, under strain controlled loading. During the loading process, the phenomenon of first hardening and then softening occurred, and the peak stress has a drop after a rapid ascent with the rising of cycles. The fatigue life of 316 LN decreases at high temperature in pure water and water with H3 BO3 and LiOH, because high temperature and corrosive environment accelerated the corrosion fatigue failure of the 316 LN. Under the condition of high strain amplitude, high temperature plays a major role in corrosion fatigue failure, while corrosion plays a major role in the condition of low strain amplitude. Fatigue striation, slip deformation zone and secondary crack can be observed on the cross section of the sample after the test. High temperature water corrosion environment will accelerate the crack growth and the fatigue failure of 316 LN.