First-principles calculation on screw dislocation core properties in BCC molybdenum

清水 大志; 尾方 成信*; 君塚 肇*; 叶野 琢磨; Li, J.*; 蕪木 英雄

Journal of the Earth Simulator, 7, p.17 - 21, 2007/06

https://doi.org/10.32131/jes.7.17

Predicting atomistic properties of a dislocation is a first step toward an understanding of plastic behavior of materials, in particular BCC metals. The core structure and Peierls stress of a screw dislocation in BCC metals have been studied over the years using the first-principles and empirical methods, however, their conclusions vary due to the inefficiency of the methods. We have executed first-principles calculations based on the density functional method, employing the most accurate 1120 k-point samplings, to determine the core structure and Peierls stress of the /2[111] screw dislocation of molybdenum. We have concluded that the core has a 6-fold structure, and determined the Peierls stress of 1.8 GPa for the simple shear strain along the (10) 111 direction.