AlMg/6082异种铝合金脉冲MIG焊缝微观组织特征和力学性能  

Microstructure and Mechanical Properties of Pulse MIG Welded Joint of AlMg/6082 Dissimilar Aluminum Alloy

作　　者：李佳 黄利 冉启洪 高峰 LI Jia;HUANG Li;RAN Qihong;GAO Feng(Department of Mechatronics and Vehicle Engineering Chongqing Jiaotong University,Chongqing 400074,China;Department of Electrical Engineering,Chongqing Industry Polytechnic College,Chongqing 401122,China;China Automotive Engineering Research Institute Co.,Ltd.,Chongqing 401120,China;Chongqing Changan Automobile Co.,Ltd.,Chongqing 400023,China)

机构地区：[1]重庆交通大学机电与车辆工程学院,重庆400074 [2]重庆工业职业技术学院电气工程学院,重庆401122 [3]中国汽车工程研究院股份有限公司部件与材料测试中心,重庆401120 [4]重庆长安汽车股份有限公司,重庆400023

出　　处：《材料导报》2025年第10期147-152,共6页Materials Reports

基　　金：重庆市教委科学技术研究项目(KJQN202203205)。

摘　　要：采用脉冲MIG焊技术连接AlMg铸铝与6082-T6铝合金型材,研究异种铝合金接头力学性能、各区域晶粒形貌、断口形貌,分析微观组织的演化对力学性能的影响规律。结果表明:6082/AlMg异种铝合金MIG焊焊接接头拉伸最大载荷为3235 N,承载为AlMg母材的85.5%,伸长率为8.2%,焊接系数约为0.8;接头断裂于AlMg母材中,呈现韧性断裂。在AlMg侧热影响区,显微硬度最低值77HV,较AlMg母材显微硬度下降仅7%,无明显软化现象,对焊接瞬时热冲击敏感性较低;而6082-T6侧热影响区软化现象明显,硬度相对母材下降32%,该软化区的形成在于β"相数量密度的降低以及强化效果较差、尺寸较大的β′相的生成。在焊接过程中,焊缝区熔池快速冷却,溶质分布不均衡,形成典型等轴晶铸态组织;受到焊接瞬时热冲击的影响,接头两侧热影响区晶粒呈现不同程度长大,其中AlMg近焊缝侧晶粒较母材晶粒尺寸长大42.8%。The joining between AlMg cast aluminum and 6082-T6 aluminum alloy was conducted with pulse MIG welding technology.The mechanical properties,grain morphology,and fracture morphology of dissimilar aluminum alloy joints between AlMg cast aluminum and 6082-T6 aluminum alloy profiles were studied.The influence of microstructural evolution on mechanical properties was analyzed.The results shows that the maximum tensile load of the 6082/AlMg welded joint is up to 3235 N,up to 85.5%of the load-bearing capacity of AlMg base material.The elongation is 8.2%,and the welding coefficient is approximately 0.8.The joints breaks in the AlMg base material and shows a ductile fracture.In the heat-affected zone on AlMg side,the lowest microhardness value is 77HV,with only a 7%decrease compared to the AlMg base metal.There is no significant softening observed,indicating a low sensitivity to the welding thermal cycle.However,the heat-affected zone of 6082-T6 side exhibits significant softening,with a 32% decrease in hardness relative to the base metal.This softening is attributed to the reduced density of β″precipitates and the formation of larger β′precipitates,which provided weaker strengthening effects.The weld zone,undergoes rapid cooling during welding,has an equiaxed dendritic cast structure with uneven solute distribution.Under the influence of the welding thermal cycle,the heat-affected zone on both sides of the joint shows varying degrees of grain growth.The AlMg side near the weld zone exhibits a 42.8%increase in grain size compared to the base metal.

关 键 词：AlMg铸铝 MIG焊 6082-T6 异种焊接 

分 类 号：TQ457[化学工程—农药化工]