Regensburg 2013 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 23: Topical Session: Combinatorial Materials Science II

MM 23.4: Vortrag

Dienstag, 12. März 2013, 12:45–13:00, H25

Ab initio study of single-crystalline and polycrystalline elastic properties of Mg-substituted calcite crystals — Li-Fang Zhu¹, •Martin Friak¹, Helge Fabritius¹, Pavlina Hemzalova¹, Andreas Ziegler², Svetoslav Nikolov³, Anna Janus¹, Dierk Raabe¹, and Joerg Neugebauer¹ — ¹Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany — ²University of Ulm, Ulm, Germany — ³Bulgarian Academy of Sciences, Sofia, Bulgaria

We employ ab initio calculations and investigate the single-crystalline elastic properties of (Ca,Mg)CO₃ crystals covering the whole range of concentrations from pure calcite CaCO₃ to pure magnesite MgCO₃. Studying different distributions of Ca and Mg atoms, our theoretical results show that the energetically most favorable configurations are characterized by elastic constants that nearly monotonously increase with the Mg content. Based on the first principles derived single-crystalline elastic anisotropy, the integral elastic response of (Ca,Mg)CO₃ polycrystals is determined employing a mean-field self-consistent homogenization method. As in case of single-crystalline elastic properties, the computed polycrystalline elastic parameters sensitively depend on the chemical composition and show a significant stiffening impact of Mg atoms on calcite crystals in agreement with experimental findings.