This research examines the structure of large angle grain boundaries using the X-ray diffraction facility at the Cornell High Energy Synchrotron Source. Atomic structure of grain boundaries is determined based on the X-ray diffraction results and modeling. The research includes a study of impurity segregation to twist boundaries and the thermal properties of grain boundaries. The program provides important, high quality data needed for accurate models of grain boundaries and gives fundamental knowledge concerning grain boundary structure shifts due to composition or temperature changes.
