The morphology of the weld seam, the formation mechanism of interface, and the microstructure and mechanical properties of both direct and AlSi12 (ER4047)-added dissimilar 5A06Al/Ti6Al4V lap joints were investigated, respectively. The Gibbs free energies of intermetallic compounds, such as TiAl3, TiAl, and Ti3Al, were calculated. The results showed that the interface layers were mainly composed of Ti3Al, TiAl, and TiAl3, and the order of them was TiAl3, TiAl, and Ti3Al from outside to inside. The addition of ER4047 interlayer could suppress the formation of IMCs and reduce the micro-cracks in TiAl₃ layer. The ER4047-added joints featured good mechanical properties, i.e., the shear strength of 2087 N, 2405 N, and 2157 N respectively, which were much higher than the shear strength of 1721 N for the direct joint. Furthermore, the fracture model of the direct joint was brittle fracture, while that of the ER4047-added joints was quasi-cleavage. The results can provide theoretical guidance for the prediction of Ti/Al interface reaction and welding of other dissimilar metals.

研究了直接和AlSi12（ER4047）添加的异种5A06Al / Ti6Al4V搭接接头的焊缝形态，界面形成机理以及显微组织和力学性能。计算了金属间化合物如TiAl3，TiAl和Ti3Al的吉布斯自由能。结果表明，界面层主要由Ti3Al，TiAl和TiAl3组成，从外到内依次为TiAl3，TiAl和Ti3Al。添加ER4047中间层可以抑制IMC的形成并减少TiAl _3中的微裂纹层。添加ER4047的接头具有良好的机械性能，即分别为2087 N，2405 N和2157 N的剪切强度，远高于直接接头的1721 N的剪切强度。此外，直接接头的断裂模型为脆性断裂，而加入ER4047的接头的断裂模型为准断裂。研究结果可为预测Ti / Al界面反应和其他异种金属的焊接提供理论指导。