Brazing of carbon fiber reinforced SiC composite and TC4 using Ag-Cu-Ti active brazing alloy

Carbon fiber reinforced SiC (Cf/SiC) was successfully joined to TC4 with Ag-Cu-Ti alloy powder by brazing. Microstructures of the brazed joints were investigated by 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 the brazed joint mainly consist of TiC, Ti3SiC2, Ti5Si3, Ag, TiCu, Ti3Cu4 and Ti2Cu reaction products. TiC + Ti3SiC2/Ti5Si3 + Ti2Cu reaction layers are formed near Cf/SiC composite side while Ti3Cu4/TiCu/Ti2Cu/Ti2Cu + Ti reaction layers are formed near TC4 side. The thickness of reaction layers of the brazed joint increases with the brazing temperature or holding time increasing. The maximum shear strengths of the brazed joints at room temperature and 500 °C with brazing temperature 900 °C and holding time 5 min are 102 and 51 MPa, respectively.