The Influence of Ti in BNi-2 High-Temperature Brazing Filler on the Interface and Properties of TZM/Inconel 718 Vacuum Brazed Joints

Using BNi-2/TiH2 (0–15wt%) composite filler metal vacuum brazed TZM/Inconel 718 brazing joints with brazing temperature of 1060 ℃. The reason for bonding the TZM joint is the diffusion zone formed by Mo, Ni, and Cr between TZM and the filler. When the Ti content was 0 and 5wt%, the content of Ti element affected the reaction layer width of the TZM and the filler material. The main components in this area were Mo, MoNi, and Cr(s,s). When the Ti content exceeded 10wt%, a large amount of (Ni, Ti) appeared, the joint became brittle, and obvious erosion of TZM was observed. In this study, the best joint strength occurs at 39.2 MPa. At this stage, the cause of joint failure is the stress concentration at the edge of the filler and TZM, which proves that the main reason affecting the mechanical properties of the TZM/Inconel 718 brazed joint is the matching of CTE. This provides a solution for optimizing the strength of future joints.