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采用变极性TIG焊接工艺对6 mm厚5B70含钪铝合金板材进行了焊接试验,对焊接接头的组织和力学性能进行了研究,分析了钪元素的作用。研究结果表明:接头的抗拉强度最高可达368 MPa,强度系数为0.89,断后伸长率为10.7%;断裂发生在熔合线处,断口形貌为韧窝;焊缝两侧硬度值最低,焊缝中心硬度稍高。在钪元素的作用下,焊缝组织得到了明显细化,熔合区形成的等轴晶层增强了焊缝与基材的相容性,热影响区的再结晶受到了抑制,接头的抗软化能力和抗拉强度提高。
The welding test was conducted on the 6 mm thick 5B70 scandium-aluminum alloy plate with the variable polarity TIG welding process. The microstructure and mechanical properties of the welded joint were studied, and the effect of scandium element was analyzed. The results show that the tensile strength of the joint is up to 368 MPa, the strength coefficient is 0.89 and the elongation after fracture is 10.7%. The fracture occurs at the fusion line and the fracture morphology is dimple. Weld center slightly higher hardness. Under the action of scandium element, the microstructure of the weld seam is obviously refined. The equiaxed grains formed in the weld zone enhance the compatibility between the weld and the substrate, and the recrystallization in the HAZ is restrained, and the softening resistance of the joint Ability and tensile strength increase.