Scopus记录号: 2-s2.0-85061150126
论文题名: Crystallographic preferred orientations of ice deformed in direct-shear experiments at low temperatures
作者: Qi C. ; Prior D.J. ; Craw L. ; Fan S. ; Llorens M.-G. ; Griera A. ; Negrini M. ; Bons P.D. ; Goldsby D.L.
刊名: Cryosphere
ISSN: 19940416
出版年: 2019
卷: 13, 期: 1 起始页码: 351
结束页码: 371
语种: 英语
英文摘要: Synthetic polycrystalline ice was sheared at temperatures of-5,-20 and-30 °C, to different shear strains, up to γ = 2.6, equivalent to a maximum stretch of 2.94 (final line length is 2.94 times the original length). Cryo-electron backscatter diffraction (EBSD) analysis shows that basal intracrystalline slip planes become preferentially oriented parallel to the shear plane in all experiments, with a primary cluster of crystal c axes (the c axis is perpendicular to the basal plane) perpendicular to the shear plane. In all except the two highest-strain experiments at-30 °C, a secondary cluster of c axes is observed, at an angle to the primary cluster. With increasing strain, the primary c-axis cluster strengthens. With increasing temperature, both clusters strengthen. In the-5 °C experiments, the angle between the two clusters reduces with strain. The c-axis clusters are elongated perpendicular to the shear direction. This elongation increases with increasing shear strain and with decreasing temperature. Highly curved grain boundaries are more prevalent in samples sheared at higher temperatures. At each temperature, the proportion of curved boundaries decreases with increasing shear strain. Subgrains are observed in all samples. Microstructural interpretations and comparisons of the data from experimentally sheared samples with numerical models suggest that the observed crystallographic orientation patterns result from a balance of the rates of lattice rotation (during dislocation creep) and growth of grains by strain-induced grain boundary migration (GBM). GBM is faster at higher temperatures and becomes less important as shear strain increases. These observations and interpretations provide a hypothesis to be tested in further experiments and using numerical models, with the ultimate goal of aiding the interpretation of crystallographic preferred orientations in naturally deformed ice. © 2019 Author(s). 资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/122677
Appears in Collections: 气候变化事实与影响
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作者单位: Department of Earth and Environmental Science, University of Pennsylvania, Philadelphia, PA, United States; Institute of Geology and Geophysics, Chinese Academy of Sciences, Beijing, China; Department of Geology, University of Otago, Dunedin, New Zealand; Departament de Geologia, Universitat Autónoma de Barcelona, Barcelona, Spain; Department of Geosciences, Eberhard Karls University of Tübingen, Tübingen, Germany
Recommended Citation:
Qi C.,Prior D.J.,Craw L.,et al. Crystallographic preferred orientations of ice deformed in direct-shear experiments at low temperatures[J]. Cryosphere,2019-01-01,13(1)