镁合金激光胶接焊接头微观及力学性能

Microstructural Characteristics and Mechanical Properties of Laser Weld Bonded Joints in Magnesium Alloy

采用激光胶接焊焊接镁合金,利用现代测试手段分析接头的微观组织特征,并分别研究激光焊、胶接和激光胶接焊3种接头在相同工艺参数下的剪切力和抗剥离力,在较好的工艺参数下,激光胶接焊焊缝成形良好。在激光热源的作用下,焊缝区内胶层受热分解并以气体形式逸出焊缝,并未影响焊缝的组织熔合;焊缝边缘附近胶层炭化裂解,存在胶层失效区,虽减小胶层的承载面积,但该区域很窄,对接头的实际承载能力影响不大。激光胶接焊接头剪切力最大,胶接接头次之,激光焊接接头剪切力最小;激光胶接焊接头的抗剥离力远大于胶接接头的抗剥离力。激光胶接焊有效提高接头的实际承载能力,因此具有很大的发展潜力。

A new joining method of Mg alloy named laser weld bonding （LWB） was adopted in which laser welding was combined with adhesive bonding. This paper presented results of recent investigations on the weldability of magnesium alloy in joints and its mechanical and microstructural properties compared with laser welded joints and adhesive bonded joints. The results indicate that, because of laser heat source existing, the adhesives in the weld are heated up and then escape in the form of gas, which can not affect the microstructure and the element distribution in the fusion zone of the weld. The adhesives near the weld are oxidized and carbonized, there is a small failure zone in the adhesive layer. Besides, it is found that the shear force of LWB joint is the highest, adhesive bonded joint is the secondary and laser welded joint is the lowest. The peel force of LWB joint is far greater than that of adhesive bonded joint. Obviously, the new technique of LWB has very large development potential for improving the load bearing capability of the joint.