对镁、铝异种金属进行激光对接焊接,研究了Mg/Al对接焊接接头组织和性能。通过SEM、EDS、XRD和显微硬度等方法对焊接接头进行结构和性能表征。结果表明,Mg-Al对接焊接时在激光功率2000 W、焊接速率2 m/min下可以得到成形良好的焊接接头。焊缝处主要生成了Al基固溶体相和Al3Mg2金属间化合物相,焊缝靠近Mg侧存在熔合线,靠近Al侧组织更加均匀。焊缝处显微硬度明显高于母材,显微硬度最大值为240 HV,最大值出现在焊缝靠近镁合金侧。 Magnesium and aluminum dissimilar metals were laser butt welded, the microstructure and properties of Mg / Al butt welded joints were studied. The structure and properties of welded joints were characterized by SEM, EDS, XRD and microhardness. The results show that a well-formed welded joint can be obtained at a laser power of 2000 W and a welding speed of 2 m / min during the butt welding of Mg-Al. The Al-based solid solution phase and the Al3Mg2 intermetallic compound phase are mainly formed in the weld, and the weld line is near the Mg side and the weld line is more uniform near the Al side. The microhardness of the weld is obviously higher than the base metal, the maximum microhardness is 240 HV, and the maximum appears in the weld near the magnesium alloy.