Interfacial microstructure and mechanical behavior of low-temperature diffusion bonded Mo/SS304 joints using NixCu1-x interlayers

To join dissimilar metals with significant differences in characteristics, such as molybdenum (Mo) and stainless steels (SS), is essential to take full advantage of their combined performances. In this work, Mo and SS304 have been jointed with Ni interlayer using a diffusion bonding technique at different bonding temperatures. The results show that a MoNi brittle intermetallic compound is easy to form in the interface of the Mo/SS304 joint with increasing the bonding temperature, which will reduce the shear strength of the joint because a crack is easy to form between Mo and the intermetallic compounds. Meanwhile, Mo/SS304 joints have also been prepared by using NixCu1-x (x = 0.45, 0.24, or 0) as an interlayer. The result shows that reducing Ni content can avoid the formation of intermetallic compounds, and the fracture occurs between the interlayer and Mo diffusion zone far away from the Mo side. This work shows that the fracture properties of the Mo/SS304 joint can be modified by changing the composition of the interlayer. The best shear strength of the Mo/SS304 joint is 140 MPa. This work is essential for effectively joining Mo and SS304 using a low-temperature diffusion bonding method.