316Ti不锈钢在模拟核电高温高压水中的腐蚀疲劳裂纹断口研究  

LOW CYCLE FATIGUE FRACTURE FOR 316Ti STAINLESS STEEL IN HIGH TEMPERATURE AND PRESSURE WATER

作　　者：徐松[1] 吴欣强[1] 韩恩厚[1] 柯伟[1] 

机构地区：[1]中国科学院金属研究所金属腐蚀与防护国家重点实验室,沈阳110016

出　　处：《中国腐蚀与防护学报》2010年第2期119-123,共5页Journal of Chinese Society For Corrosion and Protection

基　　金：国家重点基础研究规划项目(2006CB605005);中国科学院金属研究所创新基金资助

摘　　要：研究了轻水堆核电站关键设备材料316Ti不锈钢在模拟核电高温高压水环境下的低周疲劳裂纹断口,讨论了疲劳裂纹扩展、断口特征及环境致裂机理。结果表明,疲劳裂纹为穿晶扩展,且呈折线状,裂纹之间相互交叉、连接、分叉呈现出典型的多裂纹特征;高变速率时裂纹短且数目多,低应变速率时裂纹长但数目少,并且高应变速率的辉纹间距小于低应变速率时的;裂纹尖端产生严重塑性变形,并伴有一些滑移带生成,裂纹尖端或者两侧铁素体/基体界面出现二次裂纹。讨论了裂纹扩展滑移溶解机理,实验结果证实了力学和电化学反应协同作用促进了疲劳裂纹扩展,其扩展机理可用滑移溶解模型解释。Low cycle fatigue tests were performed for a type 316Ti stainless steel in high temperature and pressure water.Fatigue crack propagation,fracture behaviors and relative mechanism of environmentally assisted cracking were investigated.It was found that fatigue cracks were transgranular fracture.Cracks show tortuous behavior,and cracks were coalescence,branch deflection each other.At the high strain rate,the cracks were shorter and the number was larger,but at the low strain rate,the cracks were taller and the number was fewer.Meanwhile,striation spacing was longer at the low strain rate than that at high strain rate.Crack tip produced strongly plastic deformation and a lot of slip bands,and it was found some secondary cracks before and both sides of the crack tip.It is believed that synergism between the mechanical factors and electrochemical reactions played a key role in the process of fatigue crack propagation in high temperature water.Slip-dissolution model was proposed for explaining the related fatigue crack propagation mechanisms.

关 键 词：轻水堆核电站 低周疲劳 高温高压水 裂纹扩展 滑移溶解机理 

分 类 号：TG172.8[金属学及工艺—金属表面处理]