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MM: Fachverband Metall- und Materialphysik
MM 54: Computational Materials Modelling - Defects & Interfaces II
MM 54.2: Vortrag
Donnerstag, 14. März 2013, 12:00–12:15, H24
Ab initio stacking fault energy calculations in Mg-Y alloys — •Zongrui Pei1,2, Stefanie Sandloebes1, Stefan Zaefferer1, Alexey Dick1, Martin Friak1, Li-Fang Zhu1, Sangbong Yi3, Dietmar Letzig3, Dierk Raabe1, and Joerg Neugebauer1 — 1Max-Planck-Institut für Eisenforschung GmbH, Düsseldorf, Germany — 22Aachen Institute for Advanced Study in Computational Engineering Science (AICES), RWTH Aachen, Aachen, Germany — 3Helmholtz-Zentrum Geesthacht, Magnesium Innovation Center, Geesthacht, Germany
Pure magnesium and most commercial wrought magnesium alloys exhibit a low room temperature ductility which can be significantly increased by the addition of Y or rare earth elements (Acta Mater. 59 (2011) 429). Under- standing the mechanisms causing this ductility enhancement on an atomistic and electronic-structure level would provide a systematic approach to identify alternative favorable solutes. Therefore, in order to obtain a deeper insight into the mechanisms active in the Mg-Y alloys, a quantum-mechanical (so called ab initio) study of the compositional dependence of intrinsic stacking fault (ISF) energies has been performed. Employing density functional theory (DFT) calculations, the ISF energies have been determined within the Axial Next-Nearest-Neighbour Ising (ANNNI) model. An in-depth analysis of the theoretical data shows reduced ISF energies as a direct consequence of the dramatically reduced thermodynamic stability of hexagonal Mg-Y solid solutions when the Y concentration approaches its solubility limit in Mg (Acta Mater. 60 (2012) 3011).