AZ31B镁合金型材TIG-MIG复合焊接头的组织与力学性能  

Microstructure and Mechanical Properties of TIG-MIG Hybrid Welded Joints of AZ31B Magnesium Alloy Profile

作　　者：刘宝栓 蒋莹龙 李龙[1] 郭阳阳[1] 潘厚宏[1] LIU Baoshuan;JIANG Yinglong;LI Long;GUO Yangyang;PAN Houhong(School of Materials Science and Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学材料科学与工程学院,四川成都610031

出　　处：《热加工工艺》2020年第23期16-18,22,共4页Hot Working Technology

摘　　要：采用TIG-MIG复合焊对AZ31B镁合金挤压型材进行高速和低速焊接试验,利用光学显微镜、维氏硬度计和拉伸试验机对焊接接头的显微组织和力学性能进行了研究。结果表明:两组规范的焊接接头均成形良好,无裂纹、气孔等缺陷。接头焊缝区均为等轴晶组织,主要由α-Mg相和β-Mg17Al12析出相组成,两组规范焊接热输入量的差异使得高焊速接头的焊缝区和热影响区晶粒尺寸明显小于低焊速接头的焊缝区和热影响区晶粒尺寸。两组规范的接头的抗拉强度均达到母材的80%以上,其中高焊速接头的抗拉强度达到了母材的95%。TIG-MIG hybrid welding of AZ31B magnesium alloy extruded profiles was carried out under welding conditions of high welding speed and low welding speed. The microstructure and mechanical properties of welded joints were researched by optical microscope, vickers hardness tester and tensile tester. The results show that the welded joints have good forming without cracks, porosities and other defects. Equiaxed grains are observed in weld zone(WZ) of the welded joints.The microstructure of WZ is mainly composed of α-Mg and β-Mg17Al12 precipitated phase. The grain size of WZ and heat-affected zone(HAZ) of high speed welded joint is significantly smaller than that of low speed welded joint due to the difference of welding heat input. The tensile strength of welded joints is more than 80% of the tensile strength of base metal.And the tensile strength of high speed welded joint reaches 95% of the tensile strength of base metal.

关 键 词：镁合金 TIG-MIG复合焊 金相组织 力学性能 

分 类 号：TG457.19[金属学及工艺—焊接]