Calculation of excess free energies of precipitates via direct thermodynamic integration across phase boundaries
Journal article, 2012

We describe a technique for constraining macroscopic fluctuations in thermodynamic variables well-suited for Monte Carlo (MC) simulations of multiphase equilibria. In particular for multicomponent systems this amounts to a statistical ensemble that implements constraints on both the average composition as well as its fluctuations. The variance-constrained semi-grand-canonical (VC-SGC) ensemble allows for MC simulations, in which single-phase systems can be reversibly switched into multiphase equilibria allowing the calculation of excess free energies of precipitates of complex shapes by thermodynamic integration. The basic features as well as the scaling and convergence properties of this technique are demonstrated by an application to an Ising model. Finally, the VC-SGC MC simulation technique is used to calculate alpha/alpha' interface free energies in Fe-Cr alloys as a function of orientation and temperature taking into account configurational, vibrational, and structural degrees of freedom.


B. Sadigh

Paul Erhart

Chalmers, Applied Physics, Materials and Surface Theory

Physical Review B - Condensed Matter and Materials Physics

24699950 (ISSN) 24699969 (eISSN)

Vol. 86 13 134204

Subject Categories

Physical Chemistry

Physical Sciences

Other Physics Topics

Condensed Matter Physics


C3SE (Chalmers Centre for Computational Science and Engineering)

Areas of Advance

Materials Science



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