On the crystallography and composition of topologically close-packed phases in ATI 718Plus®
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Authors
Eggeman, AS
Hünert, D
Hardy, MC
Publication Date
2017-05-15Journal Title
Acta Materialia
ISSN
1359-6454
Publisher
Elsevier
Volume
130
Pages
271-280
Language
English
Type
Article
This Version
VoR
Metadata
Show full item recordCitation
Krakow, R., Johnstone, D., Eggeman, A., Hünert, D., Hardy, M., Rae, C., & Midgley, P. (2017). On the crystallography and composition of topologically close-packed phases in ATI 718Plus®. Acta Materialia, 130 271-280. https://doi.org/10.1016/j.actamat.2017.03.038
Abstract
ATI 718Plus® is a nickel-based superalloy developed to replace Inconel 718 in aero engines for static and rotating applications. Here, the long-term stability of the alloy was studied and it was found that topologically close-packed (TCP) phases can form at the γ-η interface or, less frequently, at grain boundaries. Conventional and scanning transmission electron microscopy techniques were applied to elucidate the crystal structure and composition of these TCP precipitates. The precipitates were found to be tetragonal sigma phase and hexagonal C14 Laves phase, both being enriched in Cr, Co, Fe and Mo though sigma has a higher Cr and lower Nb content. The precipitates were observed to be heavily faulted along multiple planes. In addition, the disorientations between the TCP phases and neighbouring η/γ were determined using scanning precession electron diffraction and evaluated in axis-angle space. This work therefore provides a series of compositional and crystallographic insights that may be used to guide future alloy design.
Keywords
Ni-based superalloys, intermetallic phases, phase composition, orientation relationship, electron diffraction
Sponsorship
The authors acknowledge Rolls-Royce plc, the EPSRC and the BMWi under grants EP/H022309/1, EP/H500375/1 and 20T0813. P.A.M acknowledges financial support from the European Research Council under the European Union's Seventh Framework Programme (FP7/2007-2013)/ERC grant agreement 291522-3DIMAGE, the Seventh Framework Programme of the European Commission: ESTEEM2, contract number 312483. DNJ acknowledges financial support from the University of Cambridge through the Cambridge Home & EU Scholarship scheme and the EPSRC Cambridge NanoDTC EP/L015978/1.
Funder references
UNIVERSITY OF BIRMINGHAM (FB EPSRC) (EP/H022309/1)
European Research Council (291522)
EPSRC (EP/H500375/1)
EPSRC (EP/L015978/1)
EC FP7 CP WITH CSA (312483)
EPSRC (EP/M005607/1)
Identifiers
External DOI: https://doi.org/10.1016/j.actamat.2017.03.038
This record's URL: https://www.repository.cam.ac.uk/handle/1810/264552
Rights
Attribution 4.0 International, Attribution 4.0 International, Attribution 4.0 International, Attribution 4.0 International