Non-equilibrium liquid phase dissolution of δ phase precipitates in a nickel-based superalloy

Abstract

A combination of Gleeble thermo-mechanical physical simulation and analytical electron microscopy techniques was used to study non-equilibrium dissolution mode of an equilibrium phase, δ phase precipitates, during rapid heating in IN 718 superalloy. In contrast to the generally reported complete solid-state dissolution, the result revealed that the precipitates dissolved by liquation reaction, which is pertinent to weldability and hot formability behavior of Nb-bearing nickel-based superalloys.

Keywords:

• nickel alloys
• laser treatment
• welding
• microstructure change
• Ni-based superalloys

Acknowledgement

The authors would like to thank Standard Aero Ltd, Winnipeg and NSERC of Canada for the financial support.