Effect of Cu foam on the microstructure and strength of the SiCf/SiC-GH536 brazed joint

The AgCuTi filler and Cu foam interlayer were used to braze silicon carbide fiber-reinforced silicon carbide matrix composites (SiCf/SiC) and nickel-based superalloy. Cu foam interlayer could reduce the brittle reaction layer on the SiCf/SiC side by diluting the brazing seam by producing Cu-based solid solution (Cu(s,s)) to inhibit Ti diffusion from the brazing filler. Cu foam did not completely disappear in the brazed joints and still maintained the basic skeleton. Sound SiCf/SiC-GH536 joints were obtained with AgCuTi filler at 890 °C for 10 min. Compared to the brazed joints without Cu foam, introducing Cu foam could enhance the overall shear strength of the brazed joints by 224%. Cu foam buffer layers provided a technique for increasing the mechanical properties of joints, promoting the use of SiCf/SiC composites in a wide range of applications.