Designing nickel base alloys for microstructural stability through low γ-γ′ interfacial energy and lattice misfit

TitleDesigning nickel base alloys for microstructural stability through low γ-γ′ interfacial energy and lattice misfit
Publication TypeJournal Article
Year of Publication2018
AuthorsMeher S., Carroll M.C, Pollock T.M, Carroll L.J
JournalMaterials and Design
Volume140
Pagination249–256
ISSN18734197
KeywordsAtom probe tomography, Interfacial energy, Precipitate coarsening, γ-γ′ nickel-base alloy
Abstract

An extended stability alloy design strategy for multicomponent γ-γ′ nickel-base alloys with near-zero lattice misfit and as low as possible interfacial energy was investigated by isothermal annealing of two experimental alloys at 900 °C for times up to 256 h. The coarsening behavior of the spherical γ′ precipitates and the phase compositions determined by atom probe tomography were utilized to exploit a modified Lifshitz-Slyozov-Wagner relationship to estimate the interfacial energies. The estimated interfacial energies are much lower than predicted by a CALPHAD-based software as well as those typically reported for multicomponent γ-γ′ nickel alloys. Despite successfully minimizing the interfacial energy and γ-γ′ lattice misfit, these factors alone were not sufficient to impart high temperature extended stability through reduced coarsening kinetics.

URLhttp://dx.doi.org/10.1016/j.matdes.2017.11.065
DOI10.1016/j.matdes.2017.11.065