铝合金电流强化激光焊接焊缝组织及性能
Microstructure and properties of aluminum alloy welded by electric current supported laser welding
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摘要: 采用电流强化激光焊接方法对3.0 mm厚的2219-T6铝合金板材进行堆焊,研究了电流对激光焊缝宏观和微观组织、气孔缺陷以及力学性能的影响.试验发现,引入电流后,焊缝区的晶粒发生明显细化,促使粗大的柱状晶转变为细小的等轴晶;而且消除了激光焊缝中央存在的羽毛状晶.与激光焊接相比,电流强化激光焊接焊缝中的气孔明显减少,接头抗拉强度明显提高.结果表明,引入电流后,焊接过程变得稳定使气孔缺陷减少,电磁搅拌作用和焦耳热效应均有利于焊缝组织细化,提高焊缝强度.Abstract: The 2219 aluminum alloy with 3 mm thickness was carried out by electric current supported laser welding, and the influences of electric current on the macrostructure, microstructure, porosity defect and mechanical properties of the weld were investigated. The results indicate that by using electric current, the coarse columnar grains transform into fine equiaxed grains and the grains are distinctly refined in weld zone. The formation of feather grains in the centre of weld during laser welding is prevented and the pores in the weld sharply reduce during electric current supported laser welding. The results show that the electric current supported laser welding process becomes more stable resulting in fewer pores in weld. The welded joints rupture at weld zone and the joint tensile strength evidently increases compared to that of laser welding. By using electric current, the grains are refined by the electromagnetic stirring and Joule heating effects, which improves the weld tensile strength.