Coarsening behaviour of gamma prime precipitates and concurrent transitions in the interface width in Ni-14 at.% Al-7 at.% Cr

Abstract

Coupling atom probe tomography and transmission electron microscopy, the temporal evolution of γ′ precipitate morphology and size distribution and compositional width of the γ/γ′ interface, have been tracked in a model Ni-14Al-7Cr (at.%) alloy, during isothermal annealing at 800 °C subsequent to rapid quenching. During the initial annealing period, coalescence-dominated growth and coarsening of γ′ precipitates are accompanied by a gradual decrease in the interface width, eventually leading to classical LSW coarsening with a constant interface width at extended annealing time periods.

Keywords:

• coarsening
• interface
• nickel superalloy
• TEM
• APT