AZ31B/Q235激光诱导电弧填丝焊连接界面分析

利用激光诱导TIG电弧复合热源，通过添加AZ61镁合金焊丝，开展了1.6 mm厚AZ31B镁合金和1.0 mm厚Q235低碳钢板材对接焊研究.分别采用扫描电镜、电子探针、万能拉伸试验机、金相显微镜等仪器进行分析测试.结果表明，采用激光诱导电弧双面填丝焊接工艺，能够获得成形美观、连续的焊缝，焊接接头平均抗拉载荷为3.13 kN.连接界面包括两部分:镁与钢的对接界面为熔化焊接，主要以界面元素扩散为主；远离对接面的接头上下界面为镁合金在钢基体的润湿铺展连接.焊接接头断裂路径表明，连接界面发生的元素扩散是实现镁合金与钢高性能连接的关键.

Analysis of AZ31B/Q235 bonding interface by laser-induced arc welding with filler wire

Butt welding of AZ31B magnesium alloy to Q235 steel sheets was conducted by utilizing laser-induced TIG heat source and AZ61 magnesium filler wire. The elemental distribution and tensile strength of the joint were examined by scanning electron microscopy (SEM), electron probe microscope analysis (EPMA), electronic tension machine and optical microscopy. The results show that a satisfied and continuous butt joint of AZ31B magnesium alloy to Q235 steel sheets was obtained. The average tensile load of the joint could reach 3.13 kN/cm, 95% of Q235 base metal. Meanwhile, the interface in the joint mainly consisted of two parts:the middle part of welded seam with diffusion between Mg and Fe; upper and lower surfaces of the steel with wetting as the main form of connection. The diffusion reaction played an important role in bonded interface of magnesium/steel dissimilar metal joint.