镁合金低脉冲激光-气体混合焊的熔池形貌演变和多级调控

利用基于COMSOL Multiphysics的脉冲激光-气体钨极电弧（GTA）混合焊接新型双热源模型，分析了焊缝沿线选定点的温度分布，研究了激光脉冲参数和电弧电流对熔池形貌的影响。工艺参数对熔池深度的影响由大到小为：激光激励电流>电弧电流>激光脉冲宽度>激光脉冲频率；工艺参数对熔池宽度的影响由大到小为：电弧电流>激光脉冲宽度或激光激励电流>激光脉冲频率。在此基础上，构建了激光诱导电弧焊接镁合金熔池形貌数据库体系，通过复合热源参数的分级调控，以实现对熔池形貌的精准控制。利用T形焊接熔池来验证熔池形貌的调控效果，结果表明控形的准确度高至95.1%。

Evolution and Multistage Regulation of Molten Pool Mor-phology by Pulsed Laser-Gas Tungsten Arc Hybrid Welding of Magnesium Alloy

With the novel dual heat source model for pulsed laser-gas tungsten arc (GTA) hybrid welding by COMSOL Multiphysics, the temperature distribution was analyzed at several selected points along the weld line. The influences of laser pulse parameters and electric arc current on the welding pool morphology were investigated. The results show that the influence of different process parameters on the depth of molten pool ranked in order is as follows: laser excitation current>arc current>laser pulse width>laser pulse frequency. The influence of different process parameters on the width of molten pool ranked in order is as follows: arc current>laser pulse width or laser excitation current>laser pulse frequency. A database of molten weld pool characteristics for laser-induced arc welding of magnesium alloy was established by classifying the composite heat source parameters and used to realize the precise control of the molten pool shape. The precise control of the actual welding molten pool of a T-shaped weld is achieved with accuracy of 95.1%.