激光-电弧复合焊接7075-T6铝合金疲劳断裂特性  

Fatigue fracture behavior of laser-MIG hybrid welded 7075-T6 aluminium alloys

作　　者：吴圣川[1,2] 徐晓波[1] 张卫华[2] 李正[1] 徐道荣[1] 

机构地区：[1]合肥工业大学材料科学与工程学院,合肥230009 [2]西南交通大学牵引动力国家重点实验室,成都610031

出　　处：《焊接学报》2012年第10期45-48,115,共4页Transactions of The China Welding Institution

基　　金：国家自然科学基金资助项目(51005068);牵引动力国家重点实验室自主课题资助项目(2012TPL_T18);汽车车身先进设计制造国家重点实验室开放基金资助项目(31115030)

摘　　要：研究激光-电弧复合焊接2 mm板7075-T6铝合金在不同应力比R和应力幅σa下的疲劳裂纹扩展行为.结果表明,优选的复合焊工艺参数激光功率3 kW、电流110A和焊接速度3 m/min条件下接头和母材的疲劳裂纹扩展速率曲线存在交叉现象,即当应力强度因子幅#K小于15.6 MPa.m1/2时,接头的疲劳裂纹扩展速率小于母材,反之则接头的疲劳裂纹扩展速率大于母材.而对应同一#K值,高应力比下的疲劳裂纹扩展速率快于低应力比条件下的扩展速率.应力幅或平均应力是影响疲劳裂纹扩展特性的主要因素.The influence of stress ratio R and stress range σa on the fatigue crack propagation behavior of high strength 7075-T6 aluminum alloy and laser-MIG hybrid welded joint is studied.The results show that under the welding parameters of P=3 000 W,I=110A and v=3 m/min,the fatigue cracking growth rate curve of laser-arc hybrid welding joint intersects with that of base metal.That is due to that the fatigue crack growth rate of hybrid welding joint is lower than that of base metal especially when the SIF range ΔK is less than 15.6 MPa·m1/2.Under the conditions of same SIF range ΔK,the fatigue cracking growth rate at the higher stress ratio is larger than that of the lower stress ratio.Furthermore,the stress range is more important than the stress ratio(mean stress) to determine the fatigue cracking growth rate of welding joints.

关 键 词：激光-电弧复合焊 7075高强铝合金 疲劳断裂 微观组织 软化效应 

分 类 号：TG456.7[金属学及工艺—焊接]