气候变化领域集成服务门户(CCPortal): Recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear

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DOI	10.5194/tc-13-1495-2019
	Recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear
	Journaux B.; Chauve T.; Montagnat M.; Tommasi A.; Barou F.; Mainprice D.; Gest L.
发表日期	2019
ISSN	19940416
EISSN	13
起始页码	1495
结束页码	1511
卷号	13 期号:5
英文摘要	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 TcU-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 TcU component. © Author(s) 2019. This work is distributed under the Creative Commons Attribution 4.0 License.
学科领域	backscatter; glacier; grain boundary; high temperature; ice; kinematics; laboratory method; microstructure; preferred orientation; slip
语种	英语
scopus关键词	backscatter; glacier; grain boundary; high temperature; ice; kinematics; laboratory method; microstructure; preferred orientation; slip
来源期刊	The Cryosphere
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/118881
作者单位	Department of Earth and Space Sciences, University of Washington, NASA Astrobiology Institute, Seattle, United States; Université Grenoble Alpes, CNRS, IRD, G-INP, IGE, Grenoble, 38000, France; PGP, Department of Geoscience, University of OsloOslo, Norway; Géosciences Montpellier, Université de Montpellier, CNRS, Montpellier, 34095, France
推荐引用方式 GB/T 7714	Journaux B.,Chauve T.,Montagnat M.,et al. Recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear[J],2019,13(5).
APA	Journaux B..,Chauve T..,Montagnat M..,Tommasi A..,Barou F..,...&Gest L..(2019).Recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear.The Cryosphere,13(5).
MLA	Journaux B.,et al."Recrystallization processes, microstructure and crystallographic preferred orientation evolution in polycrystalline ice during high-temperature simple shear".The Cryosphere 13.5(2019).