材料期刊网

采用钨极惰性气体保护焊和金属惰性气体保护焊两种工艺对T6态AA6082合金管进行焊接，比较所得焊接接头的显微组织特性和力学性能。利用光学显微镜，拉伸测试和显微硬度测试研究焊接工艺的影响。结果表明，由于形成了细小的等轴晶且枝晶间距较小，TIG焊接接头的拉伸强度比MIG焊接接头的拉伸强度高，强度可提高25%。在焊接效率方面，TIG焊接可得到更可靠的强度，与MIG焊接相比，其强度可提高25%。两种焊接工艺焊缝区的硬度都大幅度降低，这是由于高温时材料发生了相变。MIG焊接样品的硬度较低，为1.08GPa。MIG焊接接头的热影响区比TIG焊接接头的稍大，这是由于单位长度的热输出更大。

The present study is aimed to compare the microstructurecharacteristics and mechanical properties of AA6082 in T6 condition of tubular joints fabricated by tungsten inert gas welding (TIG) and metal inert gas welding (MIG) processes. The effect of welding processes was analysed based on optical microscopy image, tensile testing, and Vickers micro-hardness measurements. The results showed that the tensile strengthsof the TIG-welded joints were better than those of the MIG-welded joints, due to the contribution of fine equiaxed grains formation with narrower spacing arms. In terms of joint efficiency, the TIG process produced more reliable strength, which was about 25% higher compared to the MIG-joint. A significant decay of hardness was recorded in the adjacent of the weld bead zone, shown in both joints, related to phase transformation, induced by high temperatures experienced by material. A very low hardness, which was about 1.08GPa, was recorded in the MIG-welded specimens. The extent of the heat-affected-zone (HAZ) in the MIG-welded joints was slightly widerthan those of the TIG-welded specimens, which corresponded with a higher heat input per unit length.