Analysis of brazed joints between carbon fiber reinforced SiC composite and titanium alloy with TiC

Carbon fiber reinforced SiC(C_f/SiC) composite was successfully joined to titanium alloy with Ag-Cu-Ti-(Ti+C) mixed powder under proper parameters.The interfacial microstructure was examined with scanning electron microscope(SEM),energy dispersive spectrometer(EDS) and X-ray diffraction(XRD),and the mechanical properties of the brazed joints were tested.The results showed that Ti in the powder reacted with the composite during brazing,the resultant joints mainly consisted of TiC,Ti₃SiC₂,Ti₅Si₃,Ag,TiCu,Ti₃Cu₄ and Ti₂Cu phases.The dense bonding layers formed and were reinforced by TiC in situ synthesized from the reaction between C and Ti in the filler materials.The TiC particulates obviously relieved the thermal stress in the heterogeneous joint,resulting in an increase in shear strength of the brazed joint.The maximum shear strengths of the brazed joints at room temperature,500℃ and 800℃ reached 145 MPa,70 MPa and 39 MPa,respectively,which were remarkably higher than those brazed with C_f/SiC/Ag-Cu-Ti/TC4.