Thermodynamics of bcc metals in phase-field-crystal models

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© 2009 American Physical Society (APS). http://www.aps.org

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Journal Title

Journal ISSN

Volume Title

School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä

Date

2009

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Mcode

Degree programme

Language

en

Pages

031602/1-10

Series

Physical Review E, Volume 80, Issue 3

Abstract

We examine the influence of different forms of the free-energy functionals used in the phase-field-crystal (PFC) model, and compare them with the second-order density-functional theory (DFT) of freezing, by using bcc iron as an example case. We show that there are large differences between the PFC and the DFT and it is difficult to obtain reasonable parameters for existing PFC models directly from the DFT. Therefore, we propose a way of expanding the correlation function in terms of gradients that allows us to incorporate the bulk modulus of the liquid as an additional parameter in the theory. We show that this functional reproduces reasonable values for both bulk and surface properties of bcc iron, and therefore it should be useful in modeling bcc materials. As a further demonstration, we also calculate the grain boundary energy as a function of misorientation for a symmetric tilt boundary close to the melting transition.

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Keywords

free energy, density functional theory, correlation functions, anisotropy, liquid crystals

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Citation

Jaatinen, A. & Achim, C. V. & Elder, K. R. & Ala-Nissilä, Tapio. 2009. Thermodynamics of bcc metals in phase-field-crystal models. Physical Review E. Volume 80, Issue 3. P. 031602/1-10. ISSN 1539-3755 (printed). DOI: 10.1103/physreve.80.031602.