(深圳职业技术学院 工业中心， 深圳 518055)
摘 要: 采用CO2激光焊接系统对AZ61镁合金材料进行焊接， 研究两种不同焊接工艺条件下激光焊接接头的微观组织和化学成分的情况， 并对焊接接头进行显微硬度测试和接头拉伸实验。结果表明： AZ61镁合金CO2激光焊接接头成形良好，焊缝区域晶粒明显细化， 热影响区减小， 焊缝区域主要由细小的α-Mg相及（α+Al12Mg17）等共晶体组成； 焊缝的化学成分中铝含量明显高于母材， 而镁含量则低于母材；合金成分铝的增加有利于焊缝区域晶粒细化和力学性能的提高。 焊接接头区域的显微硬度和抗拉强度都高于母材， 焊接接头具有良好的力学性能， 说明CO2激光焊接是焊接AZ61镁合金材料的有效方法。
关键字: AZ61镁合金； 激光焊接； 力学性能； 抗拉强度
laser welding method
（Industry Center, Shenzhen Polytechnic, Shenzhen 518055, China）
Abstract: The laser welding of AZ61 magnesium alloys was carried out using a CO2 laser welding experimental system. The microstructure and chemical composition of joints were investigated under two different process conditions. The microhardness measurement and tensile test were conducted for two typical joints. The results show that the joints with good appearance have been formed. A fine grained weld region is observed and no obvious heat effected zone is found. The weld zone mainly consists of small α-Mg phase, (α+Al12Mg17) and other eutectic phases. In the weld, the composition of aluminum increases while magnesium decreases compared with those of the base metal. The increase of aluminum benefits to refine the grain and improves the mechanical properties. The test results indicate that the microhardness and tensile strength of weld zone are higher than those of the base metal. Therefore, CO2 laser welding can provide an effective method to weld the AZ61 magnesium alloys.
Key words: AZ61 magnesium alloy; laser welding; mechanical properties; tensile strength
