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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Published in:The Cryosphere
Main Authors: Journaux, Baptiste, Chauve, Thomas, Montagnat, Maurine, Tommasi, Andrea, Barou, Fabrice, Mainprice, David, Gest, Léa
Format: Article in Journal/Newspaper
Language:English
Published: Copernicus Publications 2019
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Online Access:https://doi.org/10.5194/tc-13-1495-2019
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spelling ftnonlinearchiv:oai:noa.gwlb.de:cop_mods_00002167 2023-05-15T18:32:33+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, Léa 2019-05 electronic https://doi.org/10.5194/tc-13-1495-2019 https://noa.gwlb.de/receive/cop_mods_00002167 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00002125/tc-13-1495-2019.pdf https://tc.copernicus.org/articles/13/1495/2019/tc-13-1495-2019.pdf eng eng Copernicus Publications The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424 https://doi.org/10.5194/tc-13-1495-2019 https://noa.gwlb.de/receive/cop_mods_00002167 https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00002125/tc-13-1495-2019.pdf https://tc.copernicus.org/articles/13/1495/2019/tc-13-1495-2019.pdf https://creativecommons.org/licenses/by/4.0/ uneingeschränkt info:eu-repo/semantics/openAccess CC-BY article Verlagsveröffentlichung article Text doc-type:article 2019 ftnonlinearchiv https://doi.org/10.5194/tc-13-1495-2019 2022-02-08T23:01:14Z 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 Niedersächsisches Online-Archiv NOA The Cryosphere 13 5 1495 1511
institution Open Polar
collection Niedersächsisches Online-Archiv NOA
op_collection_id ftnonlinearchiv
language English
topic article
Verlagsveröffentlichung
spellingShingle article
Verlagsveröffentlichung
Journaux, Baptiste
Chauve, Thomas
Montagnat, Maurine
Tommasi, Andrea
Barou, Fabrice
Mainprice, David
Gest, Léa
Recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear
topic_facet article
Verlagsveröffentlichung
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, Léa
author_facet Journaux, Baptiste
Chauve, Thomas
Montagnat, Maurine
Tommasi, Andrea
Barou, Fabrice
Mainprice, David
Gest, Léa
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
publishDate 2019
url https://doi.org/10.5194/tc-13-1495-2019
https://noa.gwlb.de/receive/cop_mods_00002167
https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00002125/tc-13-1495-2019.pdf
https://tc.copernicus.org/articles/13/1495/2019/tc-13-1495-2019.pdf
genre The Cryosphere
genre_facet The Cryosphere
op_relation The Cryosphere -- ˜Theœ Cryosphere -- http://www.bibliothek.uni-regensburg.de/ezeit/?2393169 -- http://www.the-cryosphere.net/ -- 1994-0424
https://doi.org/10.5194/tc-13-1495-2019
https://noa.gwlb.de/receive/cop_mods_00002167
https://noa.gwlb.de/servlets/MCRFileNodeServlet/cop_derivate_00002125/tc-13-1495-2019.pdf
https://tc.copernicus.org/articles/13/1495/2019/tc-13-1495-2019.pdf
op_rights https://creativecommons.org/licenses/by/4.0/
uneingeschränkt
info:eu-repo/semantics/openAccess
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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