Regensburg 2013 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 40: Topical Session: TEM-Symposium - In-Situ I

MM 40.4: Vortrag

Mittwoch, 13. März 2013, 16:00–16:15, H25

Real-time observation of grain boundary migration in graphene with atomic resolution — •Carl Krill¹, Simon Kurasch², Dana Zöllner³, Ossi Lehtinen⁴, Jani Kotakoski⁴, Arkady Krasheninnikov^4,5, and Ute Kaiser² — ¹Institute of Micro and Nanomaterials, Ulm University, Germany — ²Group of Electron Microscopy of Materials Science, Ulm University, Germany — ³Institute of Experimental Physics, University of Magdeburg, Germany — ⁴Department of Physics, University of Helsinki, Finland — ⁵Department of Applied Physics, Aalto University, Finland

Grain growth in polycrystalline solids is a materials science manifestation of survival of the fittest, with individual grains seizing every opportunity to steal atoms away from their neighbors. What fate befalls an atom caught in this bitter struggle, subject to the nefarious desires of two or even three neighboring grains? Until now, it has been impossible to answer this question definitively, as experimental techniques lack the spatial and temporal resolution needed to capture atomic-level dynamics during grain growth. By irradiating polycrystalline graphene with electrons in an aberration-corrected TEM, however, we show that grain growth can be studied for the first time experimentally on an atom-by-atom basis. We can watch configurational fluctuations in the boundary core region average out over time, resulting in mesoscopic translation in the direction of local curvature. The extreme case of a small graphene grain completely embedded within a larger one represents an ideal model system for testing the validity of atomic-scale computational models for grain growth.