Microstructure and mechanical properties of SiC/Inconel 718 joints brazed with CoFeCu3.5Mn3.5Cr high-entropy alloy filler

Achieving high-quality joining of silicon carbide (SiC) ceramics and Inconel 718 alloy has become a significant challenge for the brazing process, which is strongly dependent on the filler material. A novel composite interlayer consisting of high-entropy alloys (HEAs), HEA/Ni/HEA, was proposed to reduce the formation of intermetallic compounds in the brazed joints of SiC ceramics and Inconel 718 alloy. A reliable SiC/Inconel 718 brazed joint was produced at 1120 °C for 60 min. The results showed a significant reduction in the number of NiSi compounds in the brazed joint. The brazing seam structure near SiC side was filled with face-centered cubic phases with good plasticity and soft Cu-rich phases due to the high-entropy effect, which effectively suppressed the formation of intermetallic compounds. The maximum shear strength of the brazed joint reached 88 MPa, showing excellent tensile strength. The results provide a valuable basis for improving the joint quality of SiC ceramics and metals by adding high-entropy alloy fillers.