Material properties and structural perturbations at the near-atomic scale will be determined with unprecedented detail for rock-forming minerals having geophysical significance. Quantitative measurements will be made of: the waviness of low-angle grain boundaries as a function of dislocation densities; fine-scale displacements and strain produced by dislocations and grain boundaries; the spatially resolved strain-energy density near dislocation cores - regions that were previously inaccessible; and the strain fields and energies of dissociated dislocations. Geometric phase analysis, which combines high-resolution transmission electron microscopy and intensive image analysis, will be used. The measurements will be compared to calculations utilizing elastic theory. In the process, estimates of elastic constants for regions as close as one or two atomic spacings from crystallographic disruptions will be determined. The results will have implications for material properties that include deformation, recrystallization, diffusion, electrical properties and other parameters of geophysical interest. From an applied perspective, certain macroscopic boundary geometries will give curvatures that could be exploited to engineer desired properties.
Students and postdoctoral researchers with diverse backgrounds and ethnicities will be provided an interdisciplinary research environment and will be trained in advanced methods of studying materials at the nanoscale. New methodologies for studying geologic materials will be developed; the procedures and data will also be useful for scientists working in solid-state physics, chemistry, and materials science. The products of the research will be disseminated via prompt publication in leading journals with broad readership. An international component is provided through visitors who routinely utilize our facilities and techniques and export them to their home institutions and countries.
