Temperature and strain controls on ice deformation mechanisms: insights from the microstructures of samples deformed to progressively higher strains at-10,-20 and-30 degrees C
文献类型：期刊论文
| 作者 | Fan, Sheng1; Hager, Travis F.2; Prior, David J.1; Cross, Andrew J.2,3; Goldsby, David L.2; Qi, Chao4; Negrini, Marianne1; Wheeler, John5 |
| 刊名 | CRYOSPHERE
 |
| 出版日期 | 2020-11-10 |
| 卷号 | 14期号:11页码:3875-3905 |
| ISSN号 | 1994-0416 |
| DOI | 10.5194/tc-14-3875-2020 |
| 英文摘要 | In order to better understand ice deformation mechanisms, we document the microstructural evolution of ice with increasing strain. We include data from experiments at relatively low temperatures (-20 and -30 degrees C), where the microstructural evolution with axial strain has never before been documented. Polycrystalline pure water ice was deformed under a constant displacement rate (strain rate similar to 1.0 x 10(-5) s(-1)) to progressively higher strains (similar to 3 %, 5 %, 8 %, 12 % and 20 %) at temperatures of -10, -20 and -30 degrees C. Microstructural data were generated from cryogenic electron backscattered diffraction (cryo-EBSD) analyses. All deformed samples contain subgrain (low-angle misorientations) structures with misorientation axes that lie dominantly in the basal plane, suggesting the activity of dislocation creep (glide primarily on the basal plane), recovery and subgrain rotation. Grain boundaries are lobate in all experiments, suggesting the operation of strain-induced grain boundary migration (GBM). Deformed ice samples are characterized by interlocking big and small grains and are, on average, finer grained than undeformed samples. Misorientation analyses between nearby grains in 2-D EBSD maps are consistent with some 2-D grains being different limbs of the same irregular grain in the 3-D volume. The proportion of repeated (i.e. interconnected) grains is greater in the higher-temperature experiments suggesting that grains have more irregular shapes, probably because GBM is more widespread at higher temperatures. The number of grains per unit area (accounting for multiple occurrences of the same 3-D grain) is higher in deformed samples than undeformed samples, and it increases with strain, suggesting that nucleation is involved in recrystallization. "Core-and-mantle" structures (rings of small grains surrounding big grains) occur in -20 and -30 degrees C experiments, suggesting that subgrain rotation recrystallization is active. At temperatures warmer than -20 degrees C, c axes develop a crystallographic preferred orientation (CPO) characterized by a cone (i.e. small circle) around the compression axis. We suggest the c-axis cone forms via the selective growth of grains in easy slip orientations (i.e. similar to 45 degrees to shortening direction) by GBM. The opening angle of the c-axis cone decreases with strain, suggesting strain-induced GBM is balanced by grain rotation. Furthermore, the opening angle of the c-axis cone decreases with temperature. At -30 degrees C, the c-axis CPO changes from a narrow cone to a cluster, parallel to compression, with increasing strain. This closure of the c-axis cone is interpreted as the result of a more active grain rotation together with a less effective GBM. We suggest that lattice rotation, facilitated by intracrystalline dis- location glide on the basal plane, is the dominant mechanism controlling grain rotation. Low-angle neighbour-pair misorientations, relating to subgrain boundaries, are more extensive and extend to higher misorientation angles at lower temperatures and higher strains supporting a relative increase in the importance of dislocation activity. As the temperature decreases, the overall CPO intensity decreases, primarily because the CPO of small grains is weaker. High-angle grain boundaries between small grains have misorientation axes that have distributed crystallographic orientations. This implies that, in contrast to subgrain boundaries, grain boundary misorientation is not controlled by crystallography. Nucleation during recrystallization cannot be explained by sub- grain rotation recrystallization alone. Grain boundary sliding of finer grains or a different nucleation mechanism that generates grains with random orientations could explain the weaker CPO of the fine-grained fraction and the lack of crystallographic control on high-angle grain boundaries. |
| WOS关键词 | CRYSTALLOGRAPHIC PREFERRED ORIENTATIONS ; ELECTRON BACKSCATTER DIFFRACTION ; GRAIN-BOUNDARY MIGRATION ; COMPOSITE FLOW LAW ; DYNAMIC RECRYSTALLIZATION ; POLYCRYSTALLINE ICE ; FABRIC DEVELOPMENT ; SIZE REDUCTION ; PLASTIC-DEFORMATION ; MODEL DEFORMATION |
| 资助项目 | NASA Fund[NNX15AM69G] ; Marsden Fund of the Royal Society of New Zealand[UOO1116] ; Marsden Fund of the Royal Society of New Zealand[UOO052] |
| WOS研究方向 | Physical Geography ; Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000590409800002 |
| 出版者 | COPERNICUS GESELLSCHAFT MBH |
| 资助机构 | NASA Fund ; NASA Fund ; Marsden Fund of the Royal Society of New Zealand ; Marsden Fund of the Royal Society of New Zealand ; NASA Fund ; NASA Fund ; Marsden Fund of the Royal Society of New Zealand ; Marsden Fund of the Royal Society of New Zealand ; NASA Fund ; NASA Fund ; Marsden Fund of the Royal Society of New Zealand ; Marsden Fund of the Royal Society of New Zealand ; NASA Fund ; NASA Fund ; Marsden Fund of the Royal Society of New Zealand ; Marsden Fund of the Royal Society of New Zealand |
| 源URL | [http://ir.iggcas.ac.cn/handle/132A11/99890]  |
| 专题 | 地质与地球物理研究所_中国科学院地球与行星物理重点实验室 |
| 通讯作者 | Fan, Sheng |
| 作者单位 | 1.Univ Otago, Dept Geol, Dunedin, New Zealand 2.Univ Penn, Dept Earth & Environm Sci, Philadelphia, PA 19104 USA 3.Woods Hole Oceanog Inst, Dept Geol & Geophys, Woods Hole, MA 02543 USA 4.Chinese Acad Sci, Inst Geol & Geophys, Key Lab Earth & Planetary Phys, Beijing, Peoples R China 5.Univ Liverpool, Dept Earth & Ocean Sci, Liverpool, Merseyside, England |
| 推荐引用方式 GB/T 7714 | Fan, Sheng,Hager, Travis F.,Prior, David J.,et al. Temperature and strain controls on ice deformation mechanisms: insights from the microstructures of samples deformed to progressively higher strains at-10,-20 and-30 degrees C[J]. CRYOSPHERE,2020,14(11):3875-3905. |
| APA | Fan, Sheng.,Hager, Travis F..,Prior, David J..,Cross, Andrew J..,Goldsby, David L..,...&Wheeler, John.(2020).Temperature and strain controls on ice deformation mechanisms: insights from the microstructures of samples deformed to progressively higher strains at-10,-20 and-30 degrees C.CRYOSPHERE,14(11),3875-3905. |
| MLA | Fan, Sheng,et al."Temperature and strain controls on ice deformation mechanisms: insights from the microstructures of samples deformed to progressively higher strains at-10,-20 and-30 degrees C".CRYOSPHERE 14.11(2020):3875-3905. |
入库方式： OAI收割
来源：地质与地球物理研究所
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