Joining of Cf/SiBCN composite with CuPd-V filler alloy

Two compositions of CuPd-V system filler alloy were designed for joining the C_f/SiBCN composite. Their dynamic wettability on the C_f/SiBCN composite was studied with the sessile drop method. The CuPd-8V alloy exhibited a contact angle of 57° after holding at 1170?°C for 30?min, whereas for CuPd-13V alloy, a lower contact angle of 28° can be achieved after heating at 1200?°C for 20?min. Sound C_f/SiBCN joints were successfully produced using the latter filler alloy under the brazing condition of (1170-1230)°C for 10?min. The results showed that the active element V strongly diffused to the surface of C_f/SiBCN composite, with the formation of V₂C/VN reaction layer. The microstructure in the central part of the joint brazed at 1200?°C was characterized by the V₂C/VN particles distributing scatteringly in CuPd matrix. The corresponding joints showed the maximum three-point bend strength of 82.4?MPa at room temperature. When the testing temperature was increased to 600?°C, the joint strength was even elevated to 108.8?MPa. Furthermore, the joints exhibited the strength of 92.4?MPa and 39.8?MPa at 800?°C and 900?°C, respectively.