电弧电流对AZ31B/DP980激光诱导电弧焊接接头成形及力学性能的影响

采用激光诱导钨极惰性气体保护(tungsten inert gas, TIG)电弧焊接技术，在未添加任何夹层和镀层的条件下，通过优化工艺，获得了AZ31B镁合金和DP980高强钢高质量搭接焊接头，重点研究TIG电弧电流对焊接接头成形和力学性能的影响规律。结果表明：电弧电流的增大会提高镁合金在高强钢的润湿铺展能力，提升焊缝宽度的同时减小润湿角。镁合金/钢焊接接头的最大拉伸载荷随着电弧电流的增大先升高后降低，接头断裂模式由沿界面断裂转变为沿焊缝断裂。当TIG电流为80 A、激光功率为350 W时，焊接接头最大平均拉伸载荷达到279 N/mm。焊缝宽度和界面层厚度的增大以及激光匙孔的钉扎作用共同提升了镁合金/钢的接头性能。

Effect of arc current on forming and mechanical properties of AZ31B/DP980 laser-induced arc welded j oint

Without adding any interlayers or coatings, the lap welding experiment of AZ31B magnesium alloy and DP980 high-strength steel was performed with the laser-induced tungsten inert gas welding (TIG) arc technology. Through optimizing the process parameters, a high-quality lap weld joint was obtained. The effect of TIG arc current on the forming and mechanical properties of the joint was studied significantly. The results indicate that the wetting and spreading ability of magnesium alloy in high-strength steel is improved with the increase of arc current, which increases the weld width and reduces the wetting angle. Additionally, the maximum tensile load of magnesium alloy/steel welded joints increases first and then decreases with the increase of arc current and the fracture mode of the joint is changed from fracture along the interface to fracture along the weld. When the TIG current is 80 A and the laser power is 350 W, the maximum average tensile load of the welded joint reaches 279 N/mm.The increase of weld width, thickness of interfacial layer and pinning of laser keyholes together enhance the performance of magnesium alloy/steel joints.