Aging response of transient liquid phase bonded wrought IN718 superalloy: influence of post-bond heat treatment

Abstract

Aging response of transient liquid phase Nb bearing wrought IN718 nickel base superalloy is studied. The aging behaviour of the joint is influenced by low Nb+Al+Ti content of isothermal solidification zone (ISZ) and formation of Nb–Cr–Mo based boride precipitates in diffusion affected zone (DAZ). It was shown that applying a post-bond heat treatment which was able to eliminate the diffusion induced boride precipitates in DAZ and increase the Nb+Al+Ti content of the ISZ improved the aging response and shear strength of the joint.

Keywords:

• Transient liquid phase bonding
• Aging response
• Isothermal solidification
• Post-bond heat treatment

Acknowledgements

One of the authors (MP) gratefully acknowledges the support from Professor H. N. Han during his sabbatical leave in Department of Materials Science & Engineering, Seoul National University.