Brazed Joint of C_f/SiC to TC4 with TiNiNb filler materials

C_f/SiC composite and TC4 were successfully joined with the Ti_54.8Ni_34.4Nb_10.8(at.%) filler materials at 980℃ for 15 min under the vacuum condition.The melting point of Ti_54.8Ni_34.4Nb_10.8 alloy was measured by differential thermal analysis method (DTA). Microstructures of Ti_54.8Ni_34.4Nb_10.8 alloy and the brazed joints were investigated by SEM,EDS. The results showed that Ti_54.8Ni_34.4Nb_10.8 alloy consists of Ti₂Ni and Ti(Nb, Ni) phases. In the brazing process, a reaction layer consisting of TiC and NbC formed at the C_f/SiC composite interface. A diffusion layer grew on the interface of TC4 alloy. In the bonding layer, the massive Ti(Nb, Ni) phases are distributed in Ti₂Ni matrix. The C_f/SiC composite interface, where the crack generated easily, is the weakness position in brazed joints.