Brazing of C/C composites and GH3044 Ni-based superalloy using Ni71CrSi as the interlayer

C/C composites and Nickle-based superalloy GH3044 were brazed at 1 180°C for 30 min using the Ni71CrSi filler as interlayer. The wettability of filler on the surface of C/C composites and SiC modified C/C composites was studied. The microstructure, microhardness and shear fracture of the joint between C/C composites and GH3044 were investigated by scanning electron microscopy, energy-dispersive spectrometry, material universal testing machine and Micro-indentation instrument, respectively. Results showed that the joint without SiC coating got failed during the brazing process. Ni71CrSi can well braze Nickle-based superalloy and C/C composites with SiC coating. The shear strength of joint with SiC coating at room temperature was up to 35.08 MPa. The joint exhibited pseudo-plastic fracture behavior. Mechanism analysis indicated that this filler could wet modified C/C composites well. The hardness distribution of the joint presented a trend with high value at the middle and low value at the both sides, and the interfacial structure of joints was: C/C composites with SiC coating/Ni (s. s) +Cr₇C₃+Ni₃Si/Ni (s. s) +Cr₃C₂+Ni₃Si/Ni (s. s) +Cr₃C₂+MC+Ni₃Si/Ni₃Si+ MC +Ni (s. s) /GH3044.