Brazing of C_f/SiC and Ti alloy by using Ag-Cu-Ti active brazing alloy

Carbon fiber reinforced SiC(C_f/SiC) was successfully joined to TC4 with Ag-Cu-Ti alloy powder by brazing.The microstructures of the brazed joints were investigated with scanning electron microscope(SEM),energy dispersive spectrometer(EDS) and X-ray diffraction(XRD).The mechanical properties of the joints were measured with mechanical testing machine.The results show that the joints mainly consist of TiC,Ti₃SiC₂,Ti₅Si₃,Ag,TiCu,Ti₃Cu₄ and Ti₂Cu reaction products.TiC+Ti₃SiC₂/Ti₅Si₃+Ti₂Cu reaction layers are formed near C_f/SiC composite while Ti₃Cu₄/TiCu/Ti₂Cu/Ti₂Cu+Ti reaction layers are formed near TC4.The maximum room temperature and 500℃ shear strengths of the joints are 102 MPa and 51 MPa at a brazing temperature of 900℃ and a holding time of 5 min.