高温高湿下6005A-T6铝合金MIG焊对接接头的腐蚀疲劳性能  

Corrosion and fatigue resistance of MIG welding butt joint at 6005A-T6 aluminum alloy in high temperature and humidity environment

作　　者：李传迎 姜春鹏 王睿 孙晓光 LI Chuanying;JIANG Chunpeng;WANG Ru;SUN Xiaoguang(CRRC Qingdao Sifang Co.,Ltd.Qingdao,Shandong 266111)

机构地区：[1]中车青岛四方机车车辆股份有限公司,山东青岛266111

出　　处：《机车车辆工艺》2022年第3期1-4,13,共5页Locomotive & Rolling Stock Technology

基　　金：国家重点研发计划(2020YFE0204900)。

摘　　要：研究了6005A-T6铝合金及MIG焊对接接头在模拟高温高湿环境中的腐蚀疲劳行为。结果表明,6005A-T6铝合金母材及焊接接头材料在高温高湿环境中均表现出腐蚀疲劳敏感性。与6005A铝合金母材相比,焊接接头在高温高湿环境下的力学性能下降明显,中值疲劳极限下降36%,焊缝和热影响区的硬度下降29%。焊接接头疲劳性能主要受微观组织和焊缝微观缺陷的影响。在高温高湿环境中,层间微气孔易成为腐蚀源,形成弥散分布的点蚀坑。从断口特征看,裂纹起裂位置附近为解理脆性断裂,扩展区存在明显的疲劳辉纹及二次裂纹,瞬断区表现为韧窝形貌。The corrosion fatigue behaviors of the arc welding butt joint of 6005A-T6 aluminum alloy are studied in the simulated hot and humid environment. Test results show that the base material and its welded joint of 6005A-T6 aluminum alloy are sensitive to corrosion fatigue in high temperature and humidity environment. Compared with the base metal, the mechanical properties of the welded joint at 6005A aluminum alloy decrease dramatically in hot and humid environment, with the average fatigue limit declining by 36% and the hardness at the joint and HAZ decreasing by 29%. Under high temperature and humidity situations, the fatigue properties of the welded joint are mainly subject to the micro structure and micro defects at the joint. Under high temperature and humidity conditions, the micro pores at interlayers are likely the source of corrosion, forming the dispersed corrosion pit. Judging by the fracture characteristics, the area adjacent to the initial cracking position signifies splitting brittle fracture, the expansion area shows distinct fatigue striations and secondary cracking, while the instant fracture area reveals dimple morphology.

关 键 词：铝合金 焊接接头 腐蚀疲劳 高温高湿 

分 类 号：U270.41[机械工程—车辆工程]