采用TIG焊、使用与母材同质的焊丝对4.6mm厚的AZ31B变形镁合金进行焊接,利用金相显微镜、扫描电镜、显微硬度计、电子拉伸试验机等手段对焊接接头的显微组织、元素分布、断口形貌、接头硬度和强度等进行了分析。结果表明:焊缝区为细小的等轴晶,组织为α-Mg固溶体和网状分布的β-Mg17Al12金属间化合物;接头硬度分布不均匀,焊缝区最高,热影响区最低;焊缝区Mg元素烧损,Al含量较高;接头抗拉强度达到220MPa,是母材的93%,断裂发生在热影响区,断口形貌为韧-脆混合断裂。 Using TIG welding, the use of homogeneous wire with the parent material of 4.6mm thick AZ31B deformation of magnesium alloy welding, the use of metallurgical microscopy, scanning electron microscopy, microhardness tester, electronic tensile testing machine and other means of microstructure of welded joints Organization, element distribution, fracture morphology, joint hardness and strength were analyzed. The results show that the weld zone is a fine equiaxed grain and the microstructures are α-Mg solid solution and β-Mg17Al12 intermetallic compound. The hardness distribution of the joint is not uniform, the weld zone is the highest and the HAZ is the lowest. Mg element is burned and Al content is high. The joint tensile strength reaches 220MPa, which is 93% of the base material. The fracture occurs in the heat-affected zone and the fracture morphology is ductile-brittle mixed fracture.