Microstructure and mechanical strength of SiC joints brazed with Cr3C2 particulate reinforced Ag-Cu-Ti brazing alloy

Abstract Joining of SiC ceramic with Ag-Cu-Ti active alloy reinforced with Cr 3 C 2 particulates to control the microstructure and increase joint strength was investigated. The results indicated that the reaction of titanium in the brazing alloys and Cr 3 C 2 particulates was detected, but it would not affect the reaction of Ti and SiC. TiC reaction layer with a thickness about 100 nm was formed at the interface between SiC ceramic substrate and brazing alloy. Ti 5 Si 3 silicide phases were also observed near the reaction layer. The Cr 3 C 2 particulates randomly distributed in the braze matrix ( 3 C 2 ) and refined the Ag-rich and Cu-rich solid solution phase. Cu 2 Ti intermetallic phase was also found in the joint. The clustering and particle-to-particle contact behavior of Cr 3 C 2 particulates was observed in the joint with high amount of Cr 3 C 2 . The joint strength increased with increasing the volume fraction of added Cr 3 C 2 particulates first and then decreased. The shear strength of the joint brazed with 10 vol% Cr 3 C 2 addition reach up to 212.8 MPa, which was 134.2 MPa higher than that brazed with Ag-Cu-Ti brazing alloy.