Microstructure and mechanical property of C_f/SiBCN composite joint brazed with Cu-Pd-V filler alloy

Cu-Pd-V filler alloy was used to join C_f/SiBCN composite. Its dynamic wettability on the composite was studied with the sessile drop method. After heating at 1 170℃ for 30 min, the filler alloy showed a contact angle of 57°. The microstructure and phase confirmation of the joint were analyzed by SEM and XRD, respectively. When brazed at 1 170℃ for holding time of 10 min, the interfacial reactions resulted in resulted in the formation of V(C,N) reaction band with the thickness of 1 μm at the surface of C_f/SiBCN composite, and the microstructure in the central part of the joint is composed of Cu₃Pd and CuPd solid solutions. The average three-point bend strength of C_f/SiBCN-C_f/SiBCN joints at room temperature is 58.1 MPa. When the test temperature was increased to 600℃, the average joint strength was even elevated to 90.2 MPa. Eventhough the strength of brazed joints decreased at 700℃ and 800℃, which was 66.9 MPa and 64.6 MPa respectively, it still maintained at room temperature strength value.