Zr702合金焊接接头在沸腾硝酸中的腐蚀行为研究
Research on Corrosion Behavior of Zr702 Alloy Welded Joints in Boiling Nitric Acid
郭计增 1徐建平 2房菲 1刘承泽 2易全伟 1吴金平 2王丹丹 1张于胜2
作者信息
- 1. 中国核电工程有限公司,北京 100840
- 2. 西安稀有金属材料研究院有限公司,陕西 西安 710016
- 折叠
摘要
研究了采用钨极氩弧焊(TIG)焊接的Zr702合金焊接接头在 8 mol/L沸腾硝酸中的应力腐蚀、电化学腐蚀、均匀腐蚀行为及其失效机理.结果表明:TIG焊接后,Zr702合金焊接接头熔合区和热影响区晶粒发生粗化;热影响区产生残余拉应力,平行于焊缝的残余应力达到179.68 MPa,垂直于焊缝的残余应力达到 134.94 MPa.Zr702合金焊接接头的均匀腐蚀速率比母材高50%,这是由于组织内存在的残余应力会诱导合金溶解腐蚀.在拉应力的作用下,Zr702合金焊接接头表面的钝化膜沿着垂直于拉应力方向开裂,表现为明显的解理断裂特征,导致接头的应力腐蚀敏感性升高,存在应力腐蚀开裂的风险.
Abstract
The stress corrosion,electrochemical corrosion,uniform corrosion behaviors and failure mechanism of Zr702 alloy joints welded using tungsten inert gas(TIG)were investigated in 8 mol/L boiling nitric acid.The results show that the grains in the fusion zone and heat affected zone(HAZ)of Zr702 alloy welded joints undergo coarsening after welding.The residual tensile stress generates in HAZ,which is reaching 179.68 MPa and 134.94 MPa in parallel and perpendicular to the weld seam,correspondingly.The uniform corrosion rate of Zr702 alloy welded joint is 50%higher than the base material,because that the residual stress in HAZ can induce alloy dissolution corrosion.Under the action of tensile stress,the passive film on the surface of Zr702 alloy welded joint cracks along the direction perpendicular to tensile stress,exhibiting obvious cleavage fracture characteristics,resulting in increasing stress corrosion sensitivity of the joints and a risk of stress corrosion cracking.
关键词
Zr702合金/焊接接头/硝酸/应力腐蚀开裂/乏燃料后处理Key words
Zr702 alloy/welded joint/nitric acid/stress corrosion cracking/spent fuel reprocessing引用本文复制引用
基金项目
国家自然科学基金(52203383)
国家自然科学基金(12205242)
中国博士后科学基金面上项目(2023M742821)
陕西省创新能力支撑计划(2023KJXX-095)
陕西省博士后科研项目(2023BSHGZZHQYXMZZ24)
出版年
2024
NETL
NSTL
万方数据