Brown University School of Engineering

Joint Materials/Solid Mechanics Seminar: “The Phase Field Crystal Method: from Grain Growth to Solid-Vapor Interfaces”

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Monday, April 07, 2014 4:00pm - 5:00pm

Peter W. Voorhees. Departments of Materials Science and Engineering and Engineering Sciences and Applied Mathematics, Northwestern University. Phase field crystal (PFC) models have been used to describe a wide range of phenomena from grain growth to solidification and dislocation motion in crystals. The strength of the method lies in its ability to follow the atomic scale motion that accompanies a process that occurs on diffusive timescales. For example, the evolution of the dislocation structure of a grain boundary and the local atomic displacements of atoms near the boundary during grain growth will be discussed. We find that the atomic scale structure of the boundary gives rise to qualitatively new grain growth kinetics as well as both grain rotation and translation. A PFC model of a solid-vapor interface will also be discussed. We quantify the anisotropic solid-vapor surface energy and find well-developed step energies from measurements on the faceted interfaces. Additionally, the strain field beneath a stepped interface is characterized and shown to qualitatively reproduce predictions from continuum models, simulations, and experimental data. Finally, the dynamic case of step-growth of a crystal into a supersaturated vapor phase will be presented.