In-situ stabilized β-Ti in Ti-base alloys to enhance Cf/SiC-Nb heterogenous joint

A composite foil is proposed to join three-dimensional Cf/SiC to Nb substrate, which is composed of Ti-Zr-Cu-Ni amorphous foil and Ti foil, in order to reduce the brazing temperature, meanwhile keep the high serving temperature. During the brazing process, the dissolution of Ti from Ti foil and Nb from substrate into the brazing alloy was discovered. Such dissolution contributes to a variational composition and microstructure of the brazing seam. The β-Ti eutectoid transformation was suppressed. A high content of the in-situ forming (Ti,Nb) solid solution phase was observed in the brazing seam after brazing process, which is considered to be favorable for the joint for its low elastic modulus and good deformability. Defect-free joints are successfully obtained in this work using this composite foil. The maximum shear strength of the joint is measured to be 121 MPa at ambient temperature, and 83 MPa at 600 °C, respectively.