This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).
Non-technical explanation: The ability to predict the response of crystalline solids to forces that cause them to change shape, or in other words deform, is important in many areas including materials engineering, metallurgy and geoscience and has applications to problems ranging from metals forming to mountain building. This research project will investigate the deformation behavior of quartzite, a common quartz-bearing rock, at the temperatures and pressures relevant to the earth's interior. We will use a combination of in-situ synchrotron x-ray diffraction, computer based simulations and sample analysis to study the behavior of specific groups of crystals within the rock which will improve our understanding of how the behavior of groups of crystals within a rock integrate to produce the overall behavior of the rock. Our results will be most useful in understanding geological processes such as those that produce mountains or determine where in Earth's crust, earthquakes occur. However, because the deformation mechanisms that allow quartz crystals to deform are the same as those that operate in metals and ceramics, we anticipate that our results will also shed light on more general questions that have applications to a range of engineering problems. The majority of the funding requested for this project will support the education of young scientists including undergraduate, graduate and post-graduate scholars by supporting them as they participate in cutting edge research.
This project will use in-situ synchrotron x-ray diffraction from high pressure, high temperature deformation experiments on quartz combined with elastic plastic self consistent modeling and careful examination of sample microstructures to learn about the distribution of stress between grain populations during deformation. The experiments are designed to allow us to examine the relative roles of various deformation mechanisms and grain-grain interactions in generating the overall rheological behavior of polycrystalline quartz. In addition, the combination of microstructural analysis with synchrotron diffraction observations will add a great deal to the understanding and interpretation of diffraction data gathered from high pressure deformation experiments. Therefore the results from this study will have implications for and applications to deformation studies of other earth materials made with large volume high pressure apparatus, as well as ultrahigh pressure deformation studies in the diamond anvil cell (DAC) that utilize the same type of diffraction data. The results will also have implications for neutron and x-ray diffraction studies of engineering ceramics and metals.
