6005A激光-MIG复合焊接头组织及力学性能研究

为了研究高强度铝合金的焊接性能,了解激光与金属惰性气体(MIG)之间的相互作用机理,进一步优化焊接工艺参量, 采用光纤激光器与MIG复合焊焊机对3mm厚6005A铝合金进行了复合焊接试验研究。结合焊缝形貌、接头的力学性能等,分析了工艺参量对焊缝质量的影响规律。结果表明, 采用激光-MIG复合焊接6005A,在合适的工艺参量下,可以实现表面成形良好的接头;焊缝中的物相主要由-Al固溶体和弥散分布在基体中的第二相Mg2Si组成;焊缝区的显微硬度明显低于热影响区和母材的显微硬度,接头的断裂处发生在焊缝区,这是由于焊接热循环导致焊缝区组织粗化与气孔缺陷所致,接头的断裂形式为韧性断裂,断裂处呈现大量的韧窝,接头的抗拉强度为251.52MPa,可以达到母材的89.19%。焊接质量符合工程需要。

Study on microstructure and mechanical properties of 6005A joint in laser-MIG hybrid welding

In order to study the welding of high-strength aluminum alloy, understand the interaction mechanism between laser and metal inert gas (MIG) and optimize the welding process parameters further, experimental investigation on 6005A aluminum alloy with 3mm thickness in laser-MIG hybrid welding was performed using fiber laser and MIG welding machine. The influence of process parameters on weld quality was analyzed after combining weld morphology with mechanical properties of joints. The results show that a joint with good deformation for 6005A aluminum alloy under appropriate process parameters can be achieved in laser-MIG hybrid welding. Phases in the weld are mainly composed of -Al solid solution and the second phase Mg2Si dispersed in the matrix. It also is found that the hardness in the weld zone is significantly lower than that of the heat affected zone and the base metal. The fracture of welded joint occurs in the weld zone on account of microstructure coarsening and porosity defect induced by welding thermal cycle. It ruptures in the form of ductile fracture, where a lot of dimples appear. The tensile strength of the joint is 251.52MPa, 89.19% of the parent material. The weld quality meets the project requirements.