Interfacial reaction and brazing behaviour of SiC_f/SiC with C_f/C composites using Si-10Zr alloy at high temperatures

A Si-Zr eutectic alloy was employed as a high-temperature braze filler to join SiC_f/SiC composites with C_f/C composites. The interfacial microstructure and bonding mechanism on the side of the SiC_f/SiC composites were studied for the first time. The results showed that SiC reaction layers formed between the Si-Zr filler and both substrates. The SiC layer resulted from the chemical reaction between Si and C at the filler–C_f/C interface. In contrast, at the filler–SiC_f/SiC interface, coarse-SiC crystals only precipitated on the SiC fibre bundles, and there was only non-reactive bonding between the filler and the SiC matrix. In addition, the reactive infiltration process between the liquid Si alloy and the porous substrates contributed to the formation of infiltration structures, including C_f/C–SiC and SiC_f/SiC–Si-ZrSi₂, resulting in the reinforcement of the substrates and the joint. Finally, a favourable shear strength of 38 MPa was achieved.