Composite-diffusion bonding of carbon fiber reinforced C_f/SiC composite and Ti alloy with (Ti-Zr-Cu-Ni)+W composite filler

Carbon fiber reinforced SiC (C_f/SiC) was successfully vacuum brazed to Ti alloy with (Ti-Zr-Cu-Ni)+W composite filler at 930℃ for 5 min. The interface microstructure was investigated with scanning electron microscope (SEM),energy dispersive spectrometer (EDS) and X-ray diffraction (XRD). The mechanical properties of the brazed joints were measured by mechanical testing machine. The results show that Ti and Zr in the interlayer can react with the C_f/SiC composite, and the brazed seams mainly consist of Ti₃SiC₂,Ti₅Si₃,and some TiC(ZrC) reaction products. The mutual diffusion between Ti from the Ti alloy substrate and Cu and Ni from the interface formed the diffusion-reaction layer between the interlayer and Ti alloy substrate. After heat treating the brazed joint at 900℃ for 60 min,the interlayer microstructure became homogenization and the diffusion layer on TC4 alloy side thickened,and the shear strength of the joint reached 99 MPa,increased 52% comparing with that (65 MPa) before heat treatment.