Recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear
Torsion experiments were performed in polycrystalline ice at high temperature (0.97 Tm) to reproduce the simple shear kinematics that are believed to dominate in ice streams and at the base of fast-flowing glaciers. As clearly documented more than 30 years ago, under simple shear ice develops a two-...
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Language: | English |
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Copernicus Publications under license by EGU – European Geosciences Union GmbH
2019
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ftoslouniv:oai:www.duo.uio.no:10852/76368 2023-05-15T18:32:10+02:00 Recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear Journaux, Baptiste Chauve, Thomas Montagnat, Maurine Tommasi, Andrea Barou, Fabrice Mainprice, David Gest, Lea 2019-12-17T13:53:07Z http://hdl.handle.net/10852/76368 http://urn.nb.no/URN:NBN:no-79415 https://doi.org/10.5194/tc-13-1495-2019 EN eng Copernicus Publications under license by EGU – European Geosciences Union GmbH http://urn.nb.no/URN:NBN:no-79415 Journaux, Baptiste Chauve, Thomas Montagnat, Maurine Tommasi, Andrea Barou, Fabrice Mainprice, David Gest, Lea . Recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear. The Cryosphere. 2019, 13(5), 1495-1511 http://hdl.handle.net/10852/76368 1762002 info:ofi/fmt:kev:mtx:ctx&ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=The Cryosphere&rft.volume=13&rft.spage=1495&rft.date=2019 The Cryosphere 13 5 1495 1511 https://doi.org/10.5194/tc-13-1495-2019 URN:NBN:no-79415 Fulltext https://www.duo.uio.no/bitstream/handle/10852/76368/2/tc-13-1495-2019.pdf Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ CC-BY 1994-0416 Journal article Tidsskriftartikkel Peer reviewed PublishedVersion 2019 ftoslouniv https://doi.org/10.5194/tc-13-1495-2019 2020-06-21T08:54:32Z Torsion experiments were performed in polycrystalline ice at high temperature (0.97 Tm) to reproduce the simple shear kinematics that are believed to dominate in ice streams and at the base of fast-flowing glaciers. As clearly documented more than 30 years ago, under simple shear ice develops a two-maxima c axis crystallographic preferred orientation (CPO), which evolves rapidly into a single cluster CPO with a c axis perpendicular to the shear plane. Dynamic recrystallization mechanisms that occur in both laboratory conditions and naturally deformed ice are likely candidates to explain the observed CPO evolution. In this study, we use electron backscatter diffraction (EBSD) and automatic ice texture analyzer (AITA) to characterize the mechanisms accommodating deformation, the stress and strain heterogeneities that form under torsion of an initially isotropic polycrystalline ice sample at high temperature, and the role of dynamic recrystallization in accommodating these heterogeneities. These analyses highlight an interlocking microstructure, which results from heterogeneity-driven serrated grain boundary migration, and sub-grain boundaries composed of dislocations with a [c]-component Burgers vector, indicating that strong local stress heterogeneity develops, in particular, close to grain boundaries, even at high temperature and high finite shear strain. Based on these observations, we propose that nucleation by bulging, assisted by sub-grain boundary formation and followed by grain growth, is a very likely candidate to explain the progressive disappearance of the c axis CPO cluster at low angle to the shear plane and the stability of the one normal to it. We therefore strongly support the development of new polycrystal plasticity models limiting dislocation slip on non-basal slip systems and allowing for efficient accommodation of strain incompatibilities by an association of bulging and formation of sub-grain boundaries with a significant [c] component. Article in Journal/Newspaper The Cryosphere Universitet i Oslo: Digitale utgivelser ved UiO (DUO) The Cryosphere 13 5 1495 1511 |
institution |
Open Polar |
collection |
Universitet i Oslo: Digitale utgivelser ved UiO (DUO) |
op_collection_id |
ftoslouniv |
language |
English |
description |
Torsion experiments were performed in polycrystalline ice at high temperature (0.97 Tm) to reproduce the simple shear kinematics that are believed to dominate in ice streams and at the base of fast-flowing glaciers. As clearly documented more than 30 years ago, under simple shear ice develops a two-maxima c axis crystallographic preferred orientation (CPO), which evolves rapidly into a single cluster CPO with a c axis perpendicular to the shear plane. Dynamic recrystallization mechanisms that occur in both laboratory conditions and naturally deformed ice are likely candidates to explain the observed CPO evolution. In this study, we use electron backscatter diffraction (EBSD) and automatic ice texture analyzer (AITA) to characterize the mechanisms accommodating deformation, the stress and strain heterogeneities that form under torsion of an initially isotropic polycrystalline ice sample at high temperature, and the role of dynamic recrystallization in accommodating these heterogeneities. These analyses highlight an interlocking microstructure, which results from heterogeneity-driven serrated grain boundary migration, and sub-grain boundaries composed of dislocations with a [c]-component Burgers vector, indicating that strong local stress heterogeneity develops, in particular, close to grain boundaries, even at high temperature and high finite shear strain. Based on these observations, we propose that nucleation by bulging, assisted by sub-grain boundary formation and followed by grain growth, is a very likely candidate to explain the progressive disappearance of the c axis CPO cluster at low angle to the shear plane and the stability of the one normal to it. We therefore strongly support the development of new polycrystal plasticity models limiting dislocation slip on non-basal slip systems and allowing for efficient accommodation of strain incompatibilities by an association of bulging and formation of sub-grain boundaries with a significant [c] component. |
format |
Article in Journal/Newspaper |
author |
Journaux, Baptiste Chauve, Thomas Montagnat, Maurine Tommasi, Andrea Barou, Fabrice Mainprice, David Gest, Lea |
spellingShingle |
Journaux, Baptiste Chauve, Thomas Montagnat, Maurine Tommasi, Andrea Barou, Fabrice Mainprice, David Gest, Lea Recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear |
author_facet |
Journaux, Baptiste Chauve, Thomas Montagnat, Maurine Tommasi, Andrea Barou, Fabrice Mainprice, David Gest, Lea |
author_sort |
Journaux, Baptiste |
title |
Recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear |
title_short |
Recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear |
title_full |
Recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear |
title_fullStr |
Recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear |
title_full_unstemmed |
Recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear |
title_sort |
recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear |
publisher |
Copernicus Publications under license by EGU – European Geosciences Union GmbH |
publishDate |
2019 |
url |
http://hdl.handle.net/10852/76368 http://urn.nb.no/URN:NBN:no-79415 https://doi.org/10.5194/tc-13-1495-2019 |
genre |
The Cryosphere |
genre_facet |
The Cryosphere |
op_source |
1994-0416 |
op_relation |
http://urn.nb.no/URN:NBN:no-79415 Journaux, Baptiste Chauve, Thomas Montagnat, Maurine Tommasi, Andrea Barou, Fabrice Mainprice, David Gest, Lea . Recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear. The Cryosphere. 2019, 13(5), 1495-1511 http://hdl.handle.net/10852/76368 1762002 info:ofi/fmt:kev:mtx:ctx&ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=The Cryosphere&rft.volume=13&rft.spage=1495&rft.date=2019 The Cryosphere 13 5 1495 1511 https://doi.org/10.5194/tc-13-1495-2019 URN:NBN:no-79415 Fulltext https://www.duo.uio.no/bitstream/handle/10852/76368/2/tc-13-1495-2019.pdf |
op_rights |
Attribution 4.0 International https://creativecommons.org/licenses/by/4.0/ |
op_rightsnorm |
CC-BY |
op_doi |
https://doi.org/10.5194/tc-13-1495-2019 |
container_title |
The Cryosphere |
container_volume |
13 |
container_issue |
5 |
container_start_page |
1495 |
op_container_end_page |
1511 |
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1766216227755130880 |