Ab initio and atomistic study of generalized stacking fault energies in Mg and Mg-Y alloys

作者：Pei Z; Zhu L F; Friak M^*; Sandloebes S; von Pezold J; Sheng H W; Race C P; Zaefferer S; Svendsen B; Raabe D; Neugebauer J

来源：New Journal of Physics, 2013, 15(4): 043020.

DOI：10.1088/1367-2630/15/4/043020

Magnesium-yttrium 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 (so-called ab initio) 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 and (ii) a set of embedded-atom-method (EAM) potentials. These calculations predict that the addition of yttrium results in a reduction in the unstable stacking fault energy of basal slip systems. Specifically in the case of an I-2 stacking fault, the predicted reduction of the stacking fault energy due to Y atoms was verified by experimental measurements. We find a similar reduction for the stable stacking fault energy of the {11 (2) over bar2}%26lt; 11 (2) over bar3 %26gt; non-basal slip system. On the other hand, other energies along this particular gamma-surface profile increase with the addition of Y. In parallel to our quantum-mechanical calculations, we have also developed a new EAM Mg-Y potential and thoroughly tested its performance. The comparison of quantum-mechanical and atomistic results indicates that the new potential is suitable for future large-scale atomistic simulations.

• 出版日期2013-4-15