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对3mm厚的AZ61镁合金薄板采用AZ31、AZ61两种焊丝进行TIG焊,探讨焊丝成分对焊接接头组织和性能的影响。通过光镜、扫描电镜、X-ray和力学性能测试等手段,分析了两种焊丝所焊接头的外观形貌、显微组织、焊缝析出相和力学性能等的差异。结果表明:采用这两种焊丝都能获得无明显缺陷的焊接接头,AZ61焊丝的焊缝宏观形貌优于AZ31。焊缝区组织为细小等轴晶,主要存在α-Mg和β-Mg17Al12两种相,热影响区组织较粗大。采用AZ31焊丝接头的焊缝区和热影响区硬度均低于母材;采用AZ61焊丝的接头与母材相比焊缝区硬度值较高而热影响区硬度较低。拉伸断裂位置均为热影响区粗晶区。
AZ31 magnesium alloy AZ31 magnesium alloy sheet using two kinds of AZ31, AZ61 TIG welding to explore the wire composition of the welded joints and the performance of the organization. By means of light microscopy, scanning electron microscopy, X-ray and mechanical properties testing, the appearance, microstructure, weld phase and mechanical properties of the welded joints were analyzed. The results show that the weld of AZ61 welding wire is better than AZ31 in the welding joints with no obvious defects. The weld zone is composed of fine equiaxed grains, mainly including two phases, α-Mg and β-Mg17Al12, and the heat-affected zone is coarse. The hardness of weld zone and heat-affected zone with AZ31 wire joint are lower than that of base metal. The joint of AZ61 wire has higher hardness of weld zone and lower hardness of heat-affected zone than that of base metal. Tensile fracture location are heat affected zone coarse grain area.