本文以AZ31B变形镁合金为主要对象,研究镁合金的激光焊接工艺特点,探讨焊接工艺参数对接头组织及性能的影响.结果表明,激光脉宽是影响焊接接头性能的主要工艺参数,通过控制激光脉冲宽度可以获得高质量的镁合金焊接接头.组织观察发现镁合金激光焊接接头焊缝组织致密,晶粒细小,热影响区不明显;另外硬度试验显示,母材、热影响区、焊缝硬度相当.在本试验条件下采用YAG激光焊接工艺能够成功的实现变形镁合金AZ31B的连接,接头强度可达母材的95%.

The laser welding was used to weld the wrought magnesium alloy AZ31B in this paper, the technical characteristics of laser welding process was investigated, and at the same time the effects of parameters on the structures and the mechanical properties of the joint were discussed. The results showed that the pulse width was the main parameter affecting properties on the joint and the high quality joint can be obtained by controlling the pulse width. By the microstructure observation it found that the microstructures of the weld were compact, the grains were fine, and the HAZ was not distinct. In addition the results of hardness test showed that the hardness of based metal and the HAZ and the weld was equivalent. Under the condition of this experiment, the wrought magnesium alloy AZ31B could be jointed successfully by YAG laser welding process and the joint strength was up to 95% of the based metal.