Investigations on the microstructure of Mo/Ti-37.5Zr-15Cu-10Ni/Mo brazing seam

Mo/Mo joints were prepared by brazing Mo with Ti-37.5Zr-15Cu-10Ni brazing filler metal. The interaction between brazing filler metal and base metal was studied. The results showed that the liquid Ti-37.5Zr-15Cu-10Ni and Mo were diffused and dissolved, the dissolution of the base metal Mo into the brazing filler metal and the diffusion of the brazing filler metal to the base metal. With the increase of the brazing temperature, the amount of Mo dissolved in the brazing filler metal increased, and the Mo was mainly dissolved in the Ti solid solution after solidification. With the increase of the brazing temperature, the brazing filler metal diffused into grain boundaries and intergranular penetration was observed when the brazing temperature was 900 °C. In order to obtain good joint quality, avoid excessive dissolution of base metals and intergranular penetration, the temperature brazing Mo with Ti-37.5Zr-15Cu-10Ni should not be higher than 900 °C.