In Situ-Strengthened C/Sic Joint Brazed With Cu-Based Active Filler And Its Performance

Three-dimensional needled C/SiC composites were brazed in vacuum with Cu-Ti-Al active filler at 950-1040 degrees C for 10-30 min. The joint microstructure and fracture surface were characterized by optical microscopy (OM), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), X-ray diffraction (XRD), and transmission electron microscopy (TEM). A reaction layer filled with fine titanium carbide and titanium silicide grains was formed at the interface. Titanium carbide and titanium silicide particles and whiskers were also in situ formed in the brazing seam. Shear strength of the joint brazed at 970 degrees C for 15 min was 85 MPa, 33 MPa, and 18 MPa at room temperatures 600 and 800 degrees C, respectively.