Microstructure and Mechanical Property of Vacuum Brazed SiC Ceramic Joint

SiC ceramic was brazed in vacuum with Ti-35Zr-35Ni-15Cu(mass fraction/%)filler metal.The formation of interfacial structure and effects of technological parameters on joint shear strength were studied.The results show that a series of interface products form owing to the complex interface reactions between the SiC ceramic and filler metal.When the brazing temperature is 960℃for 10 min,TiC and Ti5Si3+Zr2Si layers form on the SiC ceramic side.Ti5Si3+Zr2Si grows towards to the middle of the joint and shows a long strip shape.Microstructure from SiC ceramic to the middle of the joint can be indicated as SiC/TiC/Ti5Si3+Zr2Si/Zr(s,s)/Ti(s,s)+Ti2(Cu,Ni)/(Ti,Zr)(Ni,Cu).When the brazing temperature is 960℃ for 30 min,long strip shape Ti5Si3+Zr2Si runs through the entire joint.Shear strength of the brazed joint firstly increases then decreases with the rising of the brazing temperature and holding time.The maximum shear strength of the joint with 110 MPa is obtained at brazing temperature 960℃for 10 min.