Designing nickel base alloys for microstructural stability through low γ-γ′ interfacial energy and lattice misfit. (15th February 2018)

• Record Type: Journal Article
• Authors: Meher, S.; Carroll, M.C.; Pollock, T.M.; Carroll, L.J.
• Is Part Of: Materials & design. Volume 140(2018)
• Page Start: 249
• Page End: 256
• Publication Date: 2018-02-15
• Subjects: Atom probe tomography -- γ-γ′ nickel-base alloy -- Interfacial energy -- Precipitate coarsening; Materials -- Periodicals; Engineering design -- Periodicals; Matériaux -- Périodiques; Conception technique -- Périodiques; Electronic journals; 620.11
• DOI: 10.1016/j.matdes.2017.11.065
• Languages: English
• ISSNs: 0264-1275

Abstract

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. Graphical abstract: Image 1 Highlights: Two experimental nickel-base super alloys exhibited low γ-γ' interfacial energy and a near-zero lattice mismatch. Interfacial energies estimated from experiments were much lower than simulated values. Utilization of experimentally-determined interfacial energies in simulations yield better predictions. The low interfacial energies and lattice misfits did not impart significantly improved γ' coarsening resistance.