A6N01铝合金焊接接头疲劳损伤和断口形貌分析  

Analysis of fatigue damage and fracture appearance on welded joints of A6N01 aluminum alloy

作　　者：白建颖[1] 杨尚磊[1] 贾进[1] 倪维源 

机构地区：[1]上海工程技术大学材料工程学院,上海201620

出　　处：《电焊机》2015年第6期121-124,共4页Electric Welding Machine

基　　金：国家自然科学基金资助(51075256);上海市自然科学基金资助(14ZR1418800)

摘　　要：采用高频疲劳试验机对A6N01铝合金MIG焊接试样进行低周拉伸疲劳试验,研究了A6N01铝合金焊接接头疲劳过程中表面形貌变化和疲劳断裂后的断口形貌。结果表明:随着循环应力的加载,在试样产生裂纹之前,晶界处位错塞积严重,产生永久滑移带,裂纹源萌生于永久滑移带。气孔、夹杂等缺陷处应力集中较大,也容易称为裂纹源。在裂纹扩展过程中,主裂纹对次裂纹的扩展具有屏蔽作用。裂纹在相邻的不同位向的晶粒中扩展时,裂纹扩展方向发生变化。A6N01铝合金焊接接头疲劳断口有较多浅显的韧窝,说明A6N01铝合金焊接接头具有良好塑性。The high-frequency fatigue testing machine is used to test MIG welded joints fatigue property of A6N01 aluminum alloy by the low-cycle fatigue tensile test,it is studied that how to change the A6N01 aluminum alloy welded joints during the process of fatigue and what fatigue fracture morphology is after the specimen breaks.The conclusions：With the cyclic stress loading,the grain boundary dislocation pile is serious before crack occurs resulting in permanent slip bands,which leads to crack initiation.Pores, inclusions and other defects generate large stress concentration,which lead to crack source.In the process of crack propagation,the main crack hinders the propagation of secondary crack.When the crack extends in the adjacent grains with different grain direction, the crack growth direction changes.More shallow dimples have been found on the fatigne fracture surface of wehted joints on A6N01 aluminum alloy,which indicates that plasticity of A6N01 aluminum alloy welded joints is excellent.

关 键 词：A6N01铝合金 焊接接头 裂纹 缺陷 

分 类 号：TG405[金属学及工艺—焊接]