Interfacial microstructure and mechanical properties of ZrB2SiCC ceramic and GH99 superalloy joints brazed with a Ti-modified FeCoNiCrCu high-entropy alloy

• The Ti/FeCoNiCrCu composite filler is designed based on the theory of high entropy alloy.
• The high entropy mixing keeps the activity of Ti and Cr in the braze alloy system.
• The FCC solid solution forms as the matrix of the bulk of brazing seam during brazing, which is beneficial to the property of joints.
• The joint brazed at 1180 °C for 60 min obtains the maximum shear strength of 71 MPa.

A kind of novel composite filler was designed using FeCoNiCrCu high entropy alloy and pure Ti foil. ZrB2SiCC ceramic and GH99 superalloy were brazed with the composite filler. The interfacial microstructure as well as brazing mechanism was investigated. The mechanical properties were also assessed. The results show that the high entropy mixing effect of the Ti/FeCoNiCrCu composite filler keeps the activity of Ti and Cr. The solid solution forms as the matrix of brazing seam. The phase structure of (TiB + CrB)/solid solution promise a good bond between ZSC and GH99. The interfacial reaction is affected greatly by the brazing parameters, because the activity of Ti and Cr is changed. The maximum shear strength reaches 71 MPa when the joint is brazed at 1180 °C for 60 min. Cracks primarily propagate in the ZSC away from the reaction zone.

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