Interfacial reactions and joining characteristics of a Cu-Pd-V system filler alloy with Cf/SiC composite

A novel composition of Cu-Pd-V filler alloy was designed for the joining of Cf/SiC composite. The filler alloy was fabricated into brazing foils with a thickness of 0.15 mm by a rolling process. The alloy′s wettability on the Cf/SiC composite was studied with the sessile drop method. After heating at 1473 K for 10 min the Cu-Pd-V filler alloy showed a low contact angle of 6° on the composite. A VC0.75 reaction band was formed at the surface of the Cf/SiC composite under the brazing condition of 1443 K /10 min, and the microstructure in the central part of the joint was composed of (Cu, Pd) solid solution and eutectic-like phase of Pd2Si+Cu3Pd. The interfacial reaction mechanism is discussed. The room-temperature three-point bend strength of Cf/SiC-Cf/SiC joints brazed with Cu-Pd-V filler alloy at 1443 K for 10 min is 128 MPa, and the joint strengths at temperatures of 873-1073 K are even higher than the room-temperature strength. The presence of refractory Pd2Si compounds within the joints should contribute to the stable high-temperature joint strengths.