7N01S-T5铝合金焊接接头疲劳性能  

Fatigue property of welded joint of 7N01S-T5 aluminum alloy

作　　者：魏书波[1] 刘岳[2] 刘建[1] 方喜风[1] 程永明[1] 陈辉[2] 

机构地区：[1]南车青岛四方机车车辆股份有限公司,山东青岛266111 [2]西南交通大学材料科学与工程学院,四川成都611031

出　　处：《电焊机》2015年第8期106-110,共5页Electric Welding Machine

摘　　要：对MIG焊接得到的板厚为10 mm的7N01S-T5铝合金焊接接头进行疲劳试验,研究其疲劳性能,通过对疲劳试验后的试样进行金相组织观察和断口SEM观察,分析其疲劳试验前后显微组织变化以及断裂的原因。结果表明,7N01铝合金焊接接头的疲劳极限为111.6 MPa,经过疲劳试验的焊接接头断裂在硬度值最低的焊缝处,裂纹沿垂直于焊缝柱状晶的方向扩展。疲劳源处未见明显的夹渣、气孔等缺陷。焊缝处析出相聚集在晶界,部分区域出现了液化裂纹。The fatigue test of welded joints generated in MIG welding of 10 mm thickness 7N01 aluminum alloy is conducted. Then the change of the microstructure before and after the fatigue test and the fracture reasons of samples are analyzed by microstructure and SEM observation. The result shows that the fatigue limit of the welded joints is 111.6 MPa. The welded joints after fatigue test fracture at the weld whose hardness is the lowest and the cracks extend along the direction perpendicular to the columnar grains of the weld. There is no significant slag inclusion,stomata or other defects in the fatigue source zone. Besides,the precipitates aggregate on the grain boundaries and this causes liquation cracks in partial region.

关 键 词：7N01铝合金 MIG焊 显微组织 疲劳性能 

分 类 号：TG405[金属学及工艺—焊接]