Microstructure and mechanical properties of the SiC/Zr4 joints brazed with TiZrNiCu filler for nuclear application

SiC ceramic has been successfully joined to Zr4 alloy using TiZrNiCu filler within the temperature range 1173 K-1263 K and 15 min holding time. The morphology of the SiC/Zr4 joints was investigated by SEM, and the phases in the joints were characterized by XRD and TEM. The results indicated that part of the Zr4 substrate dissolved into the molten filler during the brazing process, contributed to the increasing Zr content and the formation of Zr[Ti] solid solution in the joints. In addition, β-Ti phase was discovered in the brazing seam. This might be attributed to the existence of β-Ti stable elements, Cu and Ni. The interface characterization showed that SiC reacted with filler alloy during the brazing process, formed a (Zr, Ti)C reaction layer on SiC surface and Zr2Si compound near SiC substrate. Finally, the mechanical properties of the joints, evaluated by a shear strength test, reached a maximum of 95 MPa at the brazing temperature of 1203 K.