(1. 哈尔滨工业大学 材料科学与工程学院 先进焊接与连接国家重点实验室，哈尔滨 150001；
2. 哈尔滨工业大学 电气工程及自动化学院 自动检测与过程控制系统研究所，哈尔滨 150001)
摘 要: 以镁焊丝为填充材料，对镁/镀锌钢异种合金进行单、双光束激光熔钎焊试验研究，分析不同工艺参数对焊缝成形的影响规律，获得不同热源作用方式下的界面形态规律及其对界面强度的影响。结果表明：采用单、双光束进行填丝熔钎焊均可获得较满意的外观成形；单光束容易存在未钎合现象，焊接过程不够稳定，而双光束具有更好的温度分布，容易提高润湿铺展能力。剪切强度测试结果表明，单、双光束最大的接头效率分别达到30.9%和42.4%，焊趾处裂纹的存在是导致接头失效的主要原因。
关键字: 镁合金；镀锌钢；熔钎焊；双光束
（1. State Key Laboratory of Advanced Welding and Joining, School of Materials Science and Engineering,
Harbin Institute of Technology, Harbin 150001, China;
2. Institute of Automatic Detecting and Process Control System, School of Electrical Engineering and Automation,
Harbin Institute of Technology, Harbin 150001, China）
Abstract:The single and dual laser welding-brazing of AZ31 Mg alloy to DP980 galvanized steel was conducted with Mg filler wire. The effect of different parameters on the weld appearance was analyzed. Moreover, the interfacial pattern under different heat sources and its influence on the interfacial strength were obtained. The results indicate that good weld appearance can be achieved using both single and dual laser beam welding-brazing as filler wire. It tends to produce the lack of fusion defect by single-beam welding and the welding process is unstable. The dual-beam welding has much more uniform temperature distribution, so, the spreading-wetting ability is better than the former. The shear test results show that the highest joint efficiency of single-beam and dual-beam welding are 30.9% and 42.4%, respectively. The crack produced at the toe of weld after laser welding-brazing is the main reason for joint failure.
Key words: magnesium alloy; zinc-coated steel; welding-brazing; dual beam
