Berlin 2012 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 33: Topical Session Theory meets Experiment II - Nanocomposites and Microstructure
MM 33.2: Vortrag
Mittwoch, 28. März 2012, 12:00–12:15, TC 006
Atomic modeling of asymmetric tilt grain boundaries in Al2O3 — •Haksung Lee1, Paul Tangney2, Matthew Foulkes1, and Michael Finnis1,2 — 1Department of Physics, Imperial College London, Exhibition Road, London SW7 2AZ, UK — 2Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, UK
The atomic level characterization of grain boundaries is a fundamental subject in materials science and condensed matter physics because grain boundaries drastically affect the physical properties of polycrystalline materials. Thus the atom arrangement, termination plane, chemical composition, and electronic structure of grain boundaries, and in particular symmetric tilt grain boundaries, have been extensively investigated both experimentally and theoretically. In contrast, there are few studies of asymmetric tilt grain boundaries, despite being more prevalent, and therefore more significant to the material properties, than symmetric tilt grain boundaries.
In this presentation we introduce two symmetric and two asymmetric tilt [0001] Σ7 grain boundaries in Al2O3 through geometrical considerations. To find the stable grain boundary core structure, many configurations for each boundary were calculated using interatomic potentials. Interestingly, the grain boundary energies of the two asymmetric tilt grain boundaries are very similar to those of the symmetric tilt grain boundaries with the same Coincidence Site Lattice. We analyse the structures that emerge and compare the results with existing experimental data.