Al/Mg搅拌摩擦焊接接头组织及性能研究  

Research on Microstructure and Properties of Al/Mg Friction Stir Lap Welded Joints

作　　者：李海宁 周伟[1,2] 华鹏[1] 王云龙[1] 李先芬[1] 李玉虎 LI Haining;ZHOU Wei;HUA Peng;WANG Yunlong;LI Xianfen;LI Yuhu(School of Materials Science and Engineering,Hefei University of Technology,Hefei 230009,China;School of Mechanics and Aeronautics,Nanyang Technological University,Singapore 639798,Singapore)

机构地区：[1]合肥工业大学材料科学与工程学院,合肥230009 [2]南洋理工大学机械与航空学院,新加坡639798

出　　处：《焊管》2022年第2期25-31,共7页Welded Pipe and Tube

基　　金：安徽省自然科学基金资助项目“铁素体耐热钢搅拌摩擦焊接接头组织演变和性能特征研究”(项目编号1808085ME150)。

摘　　要：针对5052铝合金/AZ31镁合金,进行了异种搅拌摩擦焊搭接试验,通过宏观和微观分析、硬度和拉剪力测试探究了Zn中间层对于铝/镁搭接接头组织和性能的影响。结果显示,焊缝搅拌区底部形成了厚度较均匀的金属间化合物(intermetallic compounds,IMCs)层,未加Zn层时,IMCs层由铝基体、尺寸较大呈条带状的Al_(3)Mg_(2)及网格状Al_(12)Mg_(17)化合物组成,拉剪力为3.9 kN,断裂方式为解理脆性断裂;加入Zn层后,IMCs厚度随Zn中间层厚度的增加而增加,IMCs层厚度最小为330μm,内部主要由网格状Al_(12)Mg_(17)组成,网格状内部出现了小尺寸颗粒状的Mg-Zn以及Al-Mg-Zn IMCs;焊缝截面水平方向,搅拌区硬度为160HV,垂直方向硬度值最高达210HV,拉剪力最大值为4.79 kN。研究表明,生成的Mg-Zn和Al-Mg-Zn IMCs是导致拉剪力较未加Zn层时提高20%的主要原因。The dissimilar friction stir welding lap test was carried out for 5052 aluminum alloy/AZ31 magnesium alloy.The effect of Zn interlayer on the microstructure and properties of aluminum/magnesium lap joint was explored through macro and micro analysis,hardness and tensile shear test.The results show that the Intermetallic Compounds(IMCs)layer with uniform thickness is formed at the bottom of the weld stirring zone.Without Zn layer,the IMCs layer is composed of aluminum matrix,strip Al_(3)Mg_(2) and grid Al_(12)Mg_(17) compound with large size.The tensile shear force is 3.9 kN and the fracture mode is cleavage brittle fracture.After adding Zn layer,the thickness of IMCs increases with the increase of Zn interlayer thickness.When adding Zn,the minimum thickness of IMCs layer is 330μm.The IMCs layer is mainly composed of grid Al_(12)Mg_(17),and there are small-size granular Mg-Zn and Al-Mg-Zn IMCs in the grid.In the horizontal direction of the weld section,the hardness of the mixing zone is 160 HV,the hardness value in the vertical direction is up to 210 HV,and the maximum tensile shear force is 4.79 kN.The results show that the generated Mg-Zn and Al-Mg-Zn IMCs are the main reasons for the increase of tensile shear force by 20%compared with that without Zn layer.

关 键 词：搅拌摩擦焊 5052铝合金 AZ31镁合金 Zn中间层 

分 类 号：TG406[金属学及工艺—焊接]