Microstructure and mechanical characterization of Si₃N₄/nickel-based superalloy joints with Ti/Au/Ni interlayers

Abstract

The Si₃N₄ ceramic was joined to nickel-based superalloy via partial transient liquid phase bonding with Ti/Au/Ni interlayers. The interfacial microstructure and strength of joints were examined by methods of scanning electron microscopy, transmission electron microscopy, X-ray diffraction and a three-point flexural test. The results revealed the joint between Si₃N₄ and Ni interlayer consisted of TiN layer, Au-rich phase, Ni-rich phase and tiny TiO phase. The highest flexural strength of 211 MPa was achieved at room temperature, and the high-temperature strength of joints reached up to 117 MPa when testing at 1073 K. Post-bonding treatment indicated the joint strength of 120 MPa was obtained after annealing in air at 1073 K for 100 h, which exhibited superior oxidation resistant.

Keywords:

• Si₃N₄
• joining
• microstructure
• mechanical properties
• oxidation

Additional information

Funding

This work was supported by the Joint Funds of the National Natural Science Foundation of China [No. U1560202].