학술논문

Simple concentration-dependent pair interaction model for large-scale simulations of Fe-Cr alloys.
Document Type
Article
Source
Physical Review B: Condensed Matter & Materials Physics. Nov2011, Vol. 84 Issue 18, p184205-1-184205-10. 10p.
Subject
*IRON compounds
*BINARY metallic systems
*FERRITIC steel
*LATTICE theory
*DENSITY functionals
*MONTE Carlo method
Language
ISSN
1098-0121
Abstract
This work is motivated by the need for large-scale simulations to extract physical information on the ironchromium system that is a binary model alloy for ferritic steels used or proposed in many nuclear applications. From first-principles calculations and the experimental critical temperature we build a new energetic rigid lattice model based on pair interactions with concentration and temperature dependence. Density functional theory calculations in both norm-conserving and projector augmented-wave approaches have been performed. A thorough comparison of these two different ab initio techniques leads to a robust parametrization of the Fe-Cr Hamiltonian. Mean-field approximations and Monte Carlo calculations are then used to account for temperature effects. The predictions of the model are in agreement with the most recent phase diagram at all temperatures and compositions. The solubility of Cr in Fe below 700 K remains in the range of about 6 to 12%. It reproduces the transition between the ordering and demixing tendency and the spinodal decomposition limits are also in agreement with the values given in the literature. [ABSTRACT FROM AUTHOR]