Regensburg 2013 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 54: Computational Materials Modelling - Defects & Interfaces II
MM 54.3: Vortrag
Donnerstag, 14. März 2013, 12:15–12:30, H24
Ab initio and atomistic study of generalized stacking fault energies in Mg and Mg-Y alloys — •Li-Fang Zhu1, Zongrui Pei1,2, Stefanie Sandloebes1, Johann Pezold1, Martin Friak1,2, Stefan Zaefferer1, Howard Sheng3, Chris Race1, Bob Svendsen1,2,4, Dierk Raabe1, and Joerg Neugebauer1 — 1Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany — 2Aachen Institute for Advanced Study in Computational Engineering Science (AICES), RWTH Aachen, Aachen, Germany — 3George Mason University, Fairfax, USA — 4Faculty of Georesources and Materias Engineering, RWTH Aachen, Aachen, Germany
Mg-Y alloys show significantly improved room temperature ductility when compared with pure Mg. We study this interesting phenomenon theoretically at the atomic scale employing quantum-mechanical and atomistic modeling methods. Specifically, we have calculated generalized stacking fault energies for five slip systems in both elemental magnesium (Mg) and Mg-Y alloys using (i) density functional theory (DFT) and (ii) a newly developed embedded-atom method (EAM) Mg-Y potential. These calculations predict that the addition of Y results in a reduction in the unstable stacking fault energy of basal slip systems. In case of I2 stacking fault, the predicted reduction of the stacking fault energy due to Y atoms was verified by experimental TEM measurements. We find a similar reduction for the stable stacking fault energy of the 11-22<11-23> non-basal slip system. On the other hand, other energies along this particular γ-surface profile increase with the addition of Y.