摘要
为准确获得奥氏体不锈钢与液态金属的相容性,支撑其服役性能评价,本研究采用高温液态铅铋慢应变速率拉伸试验装置,开展了316NG不锈钢在3种溶解氧浓度,即低氧浓度(溶解氧浓度<7×10^(−8)%,质量百分比)、中等氧浓度(溶解氧浓度为2×10^(−6)%~2×10^(−7)%)和饱和氧浓度(溶解氧浓度为1.0×10−3%~3×10^(−4)%)下560℃液态铅铋合金(LBE)中的应力腐蚀行为研究。研究结果表明,相比于氩气环境,316NG不锈钢在液态LBE中会发生应力腐蚀现象,且随着溶解氧浓度降低,裂纹深度越深,断裂延伸率越小,应力腐蚀敏感性越明显。在低氧浓度和中等氧浓度下,316NG不锈钢的断裂模式为表面沿晶开裂和基体韧性断裂相结合的混合断裂模式;在饱和氧浓度下,316NG不锈钢的断裂模式基本为韧性断裂。316NG不锈钢发生应力腐蚀效应的主要原因是试样表面和裂纹尖端无法形成连续稳定的氧化膜,无法阻止铅铋侵蚀基体,促进沿晶裂纹生长,导致试样提前断裂失效。
To precisely obtain the compatibility between austenitic stainless steel and liquid metal for the service performance evaluation,this study used a high-temperature liquid lead-bismuth eutectic slow strain rate tensile test device to investigate the stress corrosion behavior of 316NG stainless steel in 560℃Lead-Bismuth eutectic(LBE)under three dissolved oxygen concentrations:low oxygen concentration(<7×10^(−8)%),medium oxygen concentration(2×10^(−6)%~2×10^(−7)%),and saturated oxygen concentration(1.0×10^(−3)%~3×10^(−4)%).The results show that,compared with argon environment,316NG steel exhibited stress corrosion in the LBE environment.As the dissolved oxygen concentration decreased,the crack depth increased,the fracture elongation decreased,and the stress corrosion effect became more pronounced.At low and medium oxygen concentrations,the fracture mode of 316NG steel was a mixed fracture mode which involves surface intergranular cracking and matrix ductile fracture.However,at saturated oxygen concentration,the fracture mode primarily consisted of matrix ductile fracture.The main cause of stress corrosion of 316NG steel was the inability of the specimen’s surface and crack tip to form a continuous and stable oxide film.This film is essential in preventing LBE from corroding the matrix.The interaction of LBE with the steel promotes the growth of intergranular cracks.Ultimately,it leads to premature failure of the specimen.
作者
张萍萍
龚宾
赵永福
高军
邓平
吴宗佩
Zhang Pingping;Gong Bin;Zhao Yongfu;Gao Jun;Deng Ping;Wu Zongpei(Nuclear Power Institute of China,Chengdu,610213,China)
出处
《核动力工程》
北大核心
2025年第3期152-159,共8页
Nuclear Power Engineering
基金
国家自然科学基金青年基金(52301113)。
作者简介
张萍萍(1988-),女,硕士研究生,现主要从事冷却剂化学及材料腐蚀方面的研究,E-mail:411787573@qq.com;通信作者:赵永福,E-mail:zhaoyongfu0127@126.com。
