摘要
Wrought magnesium alloy sheets were butt welded with gas metal arc welding process. Pores in the weld were investigated under different welding parameters, the causes of pore formation were systematically disposed, and the effects of porosity on the microstructure and mechanical properties of the joint were analyzed. The microstructure examination shows that the pores mainly appear close to the top or bottom part of the weld, and could connect to each other and lead to the formation of cracks in the welds. However, the pores can be controlled with proper welding parameters. The tensile testing results reveal that the average joint strength is close to or higher than that of the base metal. The microhardness in the weld can be even higher than that in the base metal due to the second ohase strengthening of β-Mg17（A1, Zn）12 formed in the weld.
使用熔化极气体保护焊对变形镁合金板材对接。在不同焊接工艺参数下观察焊缝中的气孔特征,分析气孔成因以及气孔对接头微观组织和力学性能的影响。显微组织检测结果表明:气孔主要分布在焊缝顶部或底部,而且气孔能相互连接甚至产生裂纹。然而,在合适的焊接工艺参数下,气孔的产生可以得到有效控制。拉伸测试结果表明:接头的平均抗拉强度接近甚至高于母材。由于第二相β-Mg17(Al,Zn)12的强化作用,焊缝区的硬度高于母材。
基金
Project (09009) supported by the State Key Laboratory of Advanced Welding and Joining,Harbin Institute of Technology,China
