气候变化领域集成服务门户(CCPortal): Amorphization and Plasticity of Olivine During Low-Temperature Micropillar Deformation Experiments

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DOI	10.1029/2019JB019242
	Amorphization and Plasticity of Olivine During Low-Temperature Micropillar Deformation Experiments
	Kranjc K.; Thind A.S.; Borisevich A.Y.; Mishra R.; Flores K.M.; Skemer P.
发表日期	2020
ISSN	21699313
卷号	125 期号:5
英文摘要	Experimentally quantifying the viscoplastic rheology of olivine at the high stresses and low temperatures of the shallow lithosphere is challenging due to olivine's propensity to deform by brittle mechanisms at these conditions. In this study, we use microscale uniaxial compression tests to investigate the rheology of an olivine single crystal at room pressure and temperature. Pillars with nominal diameters of 1.25 μm were prepared using a focused ion beam milling technique and were subjected to sustained axial stresses of several gigapascal. The majority of the pillars failed after dwell times ranging from several seconds to a few hours. However, several pillars exhibited clear evidence of plastic deformation without failure after 4–8 hr under load. The corresponding creep strain rates are estimated to be on the order of 10−6 to 10−7 s−1. The uniaxial stresses required to achieve this deformation (4.1–4.4 GPa) are in excellent agreement with complementary data obtained using nanoindentation techniques. Scanning transmission electron microscopy observations indicate that deformation occurred along amorphous shear bands within the deformed pillars. Electron energy loss spectroscopy measurements revealed that the bands are enriched in Fe and depleted in Mg. We propose that inhomogeneities in the cation distribution in olivine concentrate stress and promote the amorphization of the Fe-rich regions. The time dependence of catastrophic failure events suggests that the amorphous bands must grow to some critical length scale to generate an unstable defect, such as a shear crack. ©2020. American Geophysical Union. All Rights Reserved.
英文关键词	3902 creep and deformation; 3904 defects; 8033 rheology: mantle
语种	英语
来源期刊	Journal of Geophysical Research: Solid Earth
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/187840
作者单位	Institute of Materials Science and Engineering, Washington University in St. Louis, St. Louis, MO, United States; Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, TN, United States; Department of Mechanical Engineering and Materials Science, Washington University in St. Louis, St. Louis, MO, United States; Department of Earth and Planetary Sciences, Washington University in St. Louis, St. Louis, MO, United States
推荐引用方式 GB/T 7714	Kranjc K.,Thind A.S.,Borisevich A.Y.,et al. Amorphization and Plasticity of Olivine During Low-Temperature Micropillar Deformation Experiments[J],2020,125(5).
APA	Kranjc K.,Thind A.S.,Borisevich A.Y.,Mishra R.,Flores K.M.,&Skemer P..(2020).Amorphization and Plasticity of Olivine During Low-Temperature Micropillar Deformation Experiments.Journal of Geophysical Research: Solid Earth,125(5).
MLA	Kranjc K.,et al."Amorphization and Plasticity of Olivine During Low-Temperature Micropillar Deformation Experiments".Journal of Geophysical Research: Solid Earth 125.5(2020).