Diffusion bonding of a titanium alloy and a cemented carbide with Fe/V interlayer: Microstructure and mechanical properties

In this study, the YG20 and TA15 laminated structure was achieved by vacuum diffusion bonding(DB) at 940 °C/10 MPa/60 min using Fe/V double interlayer. The microstructure, compositional diffusion,and precipitate phase types of the DB interface were analyzed using SEM, EDS and EBSD. The tensile and shear properties of the DB interface were measured and the fracture mechanisms were analyzed. The results show well bonded interfaces within the laminated structure. A distinct diffusion layer was formed between TA15 and V, but no obvious diffusion layer was observed between Fe and YG20. A partial σ-phase was formed between the Fe/V interlayer materials. A diffusion layer approximately 1.98 μm in thickness developed after V diffused nearly 12 μm into the Fe foil. The shear strength and the tensile strength of the DB interface reached 145 MPa and 279 MPa. During shear and tensile testing, both DB interface fractured at the interface between the interlayer materials. The formation of the σ phase at the Fe/V diffusion layer adversely affected the DB interface quality.