【摘要】 轨道交通铝合金车体结构在运行过程中不仅承受疲劳载荷的作用，同时也受腐蚀环境的影响.本研究开展6A01-T5铝合金挤压型材焊接接头腐蚀疲劳性能测试，对比分析腐蚀环境对焊接接头疲劳性能的影响.采用MIG焊对6A01-T5铝合金型材进行对接焊接，无损检测合格后，在6A01-T5铝合金焊接试板上取疲劳试样，分别在空气环境下和3.5%氯化钠腐蚀溶液环境下开展疲劳试验，得出S-N曲线并进行断口分析.结果表明：在应力比为0.1、空气环境下6A01-T5铝合金焊接接头中值疲劳极限为91.8 MPa,而3.5%NaCl腐蚀溶液下中值疲劳极限降低为57.3 MPa,疲劳性能下降了约37.6%,腐蚀溶液使6A01-T5铝合金焊接接头在焊缝处产生腐蚀坑，在循环载荷作用下形成裂纹源，加速接头疲劳性能下降.更多还原

【Abstract】 Aluminum alloy car body structure of rail transit not only bears fatigue load, but also is affected by corrosion environment during operation. In this study, the corrosion fatigue properties of welded joints for 6A01-T5 aluminum alloy extrusion profile were studied, and the effect of corrosion environment on the fatigue properties of welded joints were compared and analyzed. The extruded 6A01-T5 aluminum alloy sheets were welded by MIG welding. The fatigue samples were taken from 6A01-T5 aluminum alloy welded sheets, which passed non-destructive inspection. Fatigue tests were carried out in air environment and 3.5% sodium chloride corrosion solution environment, respectively. The stress ratio was 0.1. S-N curves were obtained and fracture analysis was conducted. The results show that the median fatigue limit of 6A01-T5 aluminum alloy welded joint is 91.8 MPa in air environment, while 57.3 MPa in 3.5% NaCl corrosion solution. The fatigue performance in 3.5% NaCl corrosion solution is reduced by about 37.6%. This is because corrosion solution causes corrosion pits at the weld joint of 6A01-T5 aluminum alloy welded joint, forming crack sources under cyclic load, and accelerating the decline of joint fatigue performance.更多还原