Investigating spatio-temporal deformation in single crystal Ni-based superalloys using in-situ diffraction experiments and modelling
File(s)
Accepted version
Author(s)
Type
Journal Article
Abstract
In this study, we perform a detailed analysis of room temperature deformation of a [100]–orientated single
crystal Ni-based superalloy, CMSX-4 micropillar, using a combinatorial and complimentary characterisation approach of micro-Laue diffraction coupled with post-deformation microscopy and crystal plasticity modelling.
Time-resolved micro-Laue data indicated that deformation was initiated by activation of multiple slip (after 5%
engineering strain) which led to the generation of a plastic strain accumulation accompanied by a two-fold
increase in the dislocation density within the micropillar. Subsequent to that, slip occurred primarily on two systems (11̄1)[101] and (111)[1̄01] with the highest Schmid factor in the single crystal micropillar thereby resulting
in little accumulation of unpaired GNDs during a major part of the loading cycle, upto 20% strain in this case.
Finite element crystal plasticity modelling also showed good agreement with the experimental analyses, whereby
significant strains were found to develop in the above slip systems with a localisation near the centre of the
micropillar. Post-deformation transmission electron microscopy study confirmed that deformation was mediated
through a/2<110> dislocations on {111} planes in the 𝛾-phase, while high stress levels led to shearing of the 𝛾′
precipitates by a/2<110> partials bounding an anti-phase boundary free to glide on the {111} planes. During
the deformation of the single crystal micropillar, independent rotations of the 𝛾 and 𝛾′ phases were quantified by
spatially resolved post-deformation micro-Laue patterns. The degree of lattice rotation in the 𝛾-phase was higher
than that in the 𝛾′-phase.
crystal Ni-based superalloy, CMSX-4 micropillar, using a combinatorial and complimentary characterisation approach of micro-Laue diffraction coupled with post-deformation microscopy and crystal plasticity modelling.
Time-resolved micro-Laue data indicated that deformation was initiated by activation of multiple slip (after 5%
engineering strain) which led to the generation of a plastic strain accumulation accompanied by a two-fold
increase in the dislocation density within the micropillar. Subsequent to that, slip occurred primarily on two systems (11̄1)[101] and (111)[1̄01] with the highest Schmid factor in the single crystal micropillar thereby resulting
in little accumulation of unpaired GNDs during a major part of the loading cycle, upto 20% strain in this case.
Finite element crystal plasticity modelling also showed good agreement with the experimental analyses, whereby
significant strains were found to develop in the above slip systems with a localisation near the centre of the
micropillar. Post-deformation transmission electron microscopy study confirmed that deformation was mediated
through a/2<110> dislocations on {111} planes in the 𝛾-phase, while high stress levels led to shearing of the 𝛾′
precipitates by a/2<110> partials bounding an anti-phase boundary free to glide on the {111} planes. During
the deformation of the single crystal micropillar, independent rotations of the 𝛾 and 𝛾′ phases were quantified by
spatially resolved post-deformation micro-Laue patterns. The degree of lattice rotation in the 𝛾-phase was higher
than that in the 𝛾′-phase.
Date Issued
2020-03-01
Date Acceptance
2020-02-15
Citation
Materialia, 2020, 9, pp.1-14
ISSN
2589-1529
Publisher
Elsevier
Start Page
1
End Page
14
Journal / Book Title
Materialia
Volume
9
Copyright Statement
© 2020 Elsevier Ltd. All rights reserved. This manuscript is licensed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International Licence http://creativecommons.org/licenses/by-nc-nd/4.0/
Sponsor
Engineering & Physical Science Research Council (EPSRC)
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000537621200059&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Grant Number
EP/K028707/1
Subjects
Science & Technology
Technology
Materials Science, Multidisciplinary
Materials Science
Micro-Laue diffraction
CMSX-4 Single crystal superalloys
Micropillar compression
Crystal plasticity
Slip system
STRAIN-RATE SENSITIVITY
TEMPERATURE-DEPENDENCE
DISLOCATION-STRUCTURE
LAUE DIFFRACTION
VOLUME FRACTION
LATTICE MISFIT
ELASTIC-MODULI
BEHAVIOR
CREEP
MECHANISMS
Publication Status
Published
Article Number
ARTN 100635
Date Publish Online
2020-02-18