Brazing SiC ceramic to Zircaloy-4 using Zr-Ni filler alloy: Microstructure, mechanical properties and irradiation behavior

• A novel of Zr-24Ni (at.%) filler was proposed to achieve the joining of SiC ceramic and Zircaloy-4. • The wetting behavior and interfacial reaction between the Zr-Ni filler and SiC substrate were characterized. • The effect of brazing temperature on the microstructure and shear strength of the SiC/Zircaloy-4 joint was discussed. • He ion irradiation behavior in SiC/brazing seam interface was studied for the first time using TEM. SiC ceramic was successfully brazed to Zircaloy-4 using Zr-24Ni (at.%) filler alloy for nuclear application. The wetting behavior and interfacial reaction between the Zr-Ni filler and SiC substrate were studied. The results showed that the Zr-Ni filler possessed excellent wettability (wetting angle ∼ 4°) on the SiC substrate, and the interfacial reaction products of ZrC and Zr 2 Si were formed. The effect of brazing temperature on the microstructure and shear strength of the SiC/Zircaloy-4 joint were investigated. When the brazing temperature was lower than 1060 °C, the interface reaction of the joint was weak and the joint was mainly composed of SiC/ZrC/Zr 2 Ni +Zr-based solid solution/Zircaloy-4. When the brazing temperature was higher than 1060 °C, the interface reaction was enhanced and the Zr 2 Si phase appeared in the joint. The maximum shear strength of the joint was 110 MPa at a brazing parameter of 1060 °C for 15 min due to the moderate interface reaction between filler and substrates. Moreover, the experiment of He ion irradiation on the joint at room temperature showed that no significant irradiation damage appeared for SiC, ZrC and Zr 2 Ni in the joints when the irradiation fluence was lower than 1 × 10 16 ions/cm 2 . However, when the irradiation fluence was higher than 5 × 10 16 ions/cm 2 , the transformation of SiC and Zr 2 Ni from crystalline into amorphous state was observed. As the irradiation fluence increased, microcracks appeared in SiC and ZrC due to the uncoordinated irradiation swelling between them.