In-situ Synchrotron X-ray Diffraction Study of Quartz Deformation

该奖项根据 2009 年《美国复苏和再投资法案》（公法 111-5）提供资金。 非技术解释：预测结晶固体对导致其形状改变或变形的力的响应的能力在包括材料工程、冶金和地球科学在内的许多领域都很重要，并且可应用于从金属成型到造山等各种问题。该研究项目将研究石英岩（一种常见的含石英岩石）在与地球内部相关的温度和压力下的变形行为。我们将结合使用原位同步加速器 X 射线衍射、基于计算机的模拟和样品分析来研究岩石内特定晶体群的行为，这将提高我们对岩石内晶体群的行为如何整合以产生岩石整体行为的理解。 我们的结果对于理解地质过程非常有用，例如产生山脉的地质过程或确定地震在地壳中发生的位置。 然而，由于石英晶体变形的变形机制与金属和陶瓷中的变形机制相同，因此我们预计我们的结果也将阐明可应用于一系列工程问题的更普遍的问题。 该项目申请的大部分资金将用于支持包括本科生、研究生和研究生学者在内的年轻科学家的教育，支持他们参与前沿研究。技术说明：该项目将利用石英高压高温变形实验的原位同步加速器X射线衍射，结合弹塑性自洽建模和对样品微观结构的仔细检查，以了解变形过程中晶粒群体之间的应力分布。 这些实验旨在让我们能够检查各种变形机制和晶粒间相互作用在产生多晶石英的整体流变行为中的相对作用。 此外，微观结构分析与同步加速器衍射观测的结合将极大地促进对高压变形实验收集的衍射数据的理解和解释。 因此，本研究的结果将对使用大体积高压装置制造的其他地球材料的变形研究以及利用相同类型的衍射数据的金刚石砧室（DAC）的超高压变形研究具有影响和应用。 研究结果还将对工程陶瓷和金属的中子和 X 射线衍射研究产生影响。

This award is funded under the American Recovery and Reinvestment Act of2009 (Public Law 111-5).Non-technical explanation:The ability to predict the response of crystalline solids to forces thatcause them to change shape, or in other words deform, is important in manyareas including materials engineering, metallurgy and geoscience and hasapplications to problems ranging from metals forming to mountain building. This research project will investigate the deformation behavior ofquartzite, a common quartz-bearing rock, at the temperatures and pressuresrelevant to the earth's interior. We will use a combination of in-situsynchrotron x-ray diffraction, computer based simulations and sampleanalysis to study the behavior of specific groups of crystals within therock which will improve our understanding of how the behavior of groups ofcrystals within a rock integrate to produce the overall behavior of therock. Our results will be most useful in understanding geologicalprocesses such as those that produce mountains or determine where inEarth's crust, earthquakes occur. However, because the deformationmechanisms that allow quartz crystals to deform are the same as those thatoperate in metals and ceramics, we anticipate that our results will alsoshed light on more general questions that have applications to a range ofengineering problems. The majority of the funding requested for thisproject will support the education of young scientists includingundergraduate, graduate and post-graduate scholars by supporting them asthey participate in cutting edge research.Technical explanation:This project will use in-situ synchrotron x-ray diffraction from highpressure, high temperature deformation experiments on quartz combined withelastic plastic self consistent modeling and careful examination of samplemicrostructures to learn about the distribution of stress between grainpopulations during deformation. The experiments are designed to allow usto examine the relative roles of various deformation mechanisms andgrain-grain interactions in generating the overall rheological behavior ofpolycrystalline quartz. In addition, the combination of microstructuralanalysis with synchrotron diffraction observations will add a great dealto the understanding and interpretation of diffraction data gathered fromhigh pressure deformation experiments. Therefore the results from thisstudy will have implications for and applications to deformation studiesof other earth materials made with large volume high pressure apparatus,as well as ultrahigh pressure deformation studies in the diamond anvilcell (DAC) that utilize the same type of diffraction data. The resultswill also have implications for neutron and x-ray diffraction studies ofengineering ceramics and metals.