热带海洋大气条件下2195铝锂合金搅拌摩擦焊接头腐蚀行为  

Corrosion behavior of 2195 aluminum-lithium alloy stir friction welded joints under tropical marine atmospheric conditions

作　　者：胡启达 张华[1] 王彩妹 程东海 Hu Qida;Zhang Hua;Wang Caimei;Cheng Donghai(Beijing Institute of Petrochemical Engineering,Beijing 102617,China)

机构地区：[1]北京石油化工学院,北京102617

出　　处：《焊接》2022年第5期8-13,共6页Welding & Joining

基　　金：国家自然科学基金资助项目(51774047);北京市长城学者培养计划项目(CIT&TCD20170309);北京石油化工学院重要科研成果培育资助项目(BIPTACF-009)。

摘　　要：针对2195铝锂合金暴露在热带海洋大气条件下的服役,通过金相观察、透射电镜(TEM)观察、腐蚀形貌观察及力学性能测试研究其腐蚀行为。结果表明,热影响区腐蚀较焊缝强烈,这是由于热影响区存在T相,焊缝不存在T相;焊接件腐蚀的主要形式为剥落腐蚀;暴露3个月后,焊件出现起皮现象;暴露6个月后,腐蚀坑面积扩大,连接成腐蚀带,同时腐蚀坑开始变深,焊接件的拉伸性能明显降低;12个月后腐蚀坑深度达到22.7μm,接头抗拉强度与断后伸长率均明显下降,由暴露3个月的449.45 MPa降低到暴露12个月的373.25 MPa,断后伸长率由11.254%降低到7.756%;在腐蚀过程中,焊缝的腐蚀坑最深处深度变化速率保持稳定,约为5μm/月。For 2195 aluminum-lithium alloy exposed to tropical marine atmospheric conditions of service,its corrosion behavior was researched through metallographic observation,transmission electron microscopy(TEM)observation,corrosion morphology observation and mechanical properties testing.The results showed that corrosion of heat affected zone was stronger than that of weld,which was due to the presence of T_(1) phase in heat affected zone,while weld did not exist T_(1) phase.Main corrosion form of welded parts was spalling corrosion.After 3 months of exposure,welded parts appeared skinning phenomenon.After 6 months of exposure,area of corrosion pits expanded and they were connected into a corrosion zone.Meanwhile,corrosion pits began to become deeper,tensile properties of welded parts was significantly reduced.After 12 months of exposure,depth of corrosion pits reached 22.7μm.Tensile strength and elongation of welded joints were significantly reduced,tensile strength was reduced from 449.45 MPa after 3 months of exposure to 373.25 MPa after 12 months of exposure,and elongation was reduced from 11.254%to 7.756%.In corrosion process,change rate of corrosion pits of weld at the deepest depth remained stable,about 5μm/month.

关 键 词：铝锂合金 搅拌摩擦焊 热带海洋大气 腐蚀行为 抗拉强度 

分 类 号：TG453.9[金属学及工艺—焊接]