Diffusion bonding of (Hf(0.2)Zr(0.2)Ti(0.2)Ta(0.2)Nb0.2)C high-entropy ceramic with metallic Ni foil

To prepare large-sized and complex-shaped components, the feasibility of direct diffusion bonding of (Hf0.2Zr0.2Ti0.2Ta0.2Nb0.2)C high-entropy ceramic (HEC) and its diffusion bonding with a metallic Ni foil was investigated, and the interfacial microstructure and mechanical properties of HEC/HEC and HEC/Ni/HEC joints were analyzed. For the direct diffusion bonding, reliable joints with a shear strength of 146 MPa could be achieved when the bonding temperature reached 1500 degrees C under a pressure of 30 MPa. By introducing a metallic Ni foil as the interlayer, the HEC was successfully bonded at the diffusion temperatures from 1150 degrees C to 1250 degrees C under 10 MPa through the formation of Ti2Ni compound phase. Meanwhile, the HEC(Ni) phase formed by the diffusion of Ni into HEC and Ni(s, s) bulks precipitated in the bonding transition zone. The maximum joint shear strength of 151 MPa was obtained by optimizing the Ni-foil thickness, bonding temperature, and holding time.

Automated summary

The study successfully achieved the bonding of (Hf0.2Zr0.2Ti0.2Ta0.2Nb0.2)C high-entropy ceramic through direct diffusion bonding and a metallic Ni foil as an interlayer, demonstrating reliable mechanical properties.