Joining C/C composite to Nb-1Zr alloy using a novel CoCrFeNiCuTi0.25 high-entropy filler

In this study, C/C composite and Nb-1Zr alloy were reliably brazed using a novel CoCrFeNiCuTi0.25 (at%) high-entropy filler alloy. The effects of the brazing temperature and holding time on the microstructure and mechanical properties of the joints were investigated. The results showed that the typical C/C and Nb-1Zr joint consisted of C/C/ (Ti,Nb)C/ (Nb,Ti)/ FCC1 + FCC2 + Cu(s,s)/ Nb-1Zr. With an increase in the brazing temperature or extension of the holding time, the thickness of the (Nb,Ti) layer and content of the brittle phases in the brazing layer increased, whereas the content of plastic phases with the face-centered cubic structure decreased. An optimized average shear strength of 47.44 MPa was obtained when the joints were brazed at 1175 ℃ for 10 min.