| 1. |
- Becker, Chandler A., et al.
(författare)
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Thermodynamic modelling of liquids : CALPHAD approaches and contributions from statistical physics
- 2014
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Ingår i: Physica status solidi. B, Basic research. - : Wiley. - 0370-1972 .- 1521-3951. ; 251:1, s. 33-52
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Tidskriftsartikel (refereegranskat)abstract
- We describe current approaches to thermodynamic modelling of liquids for the CALPHAD method, the use of available experimental methods and results in this type of modelling, and considerations in the use of atomic-scale simulation methods to inform a CALPHAD approach. We begin with an overview of the formalism currently used in CALPHAD to describe the temperature dependence of the liquid Gibbs free energy and outline opportunities for improvement by reviewing the current physical understanding of the liquid. Brief descriptions of experimental methods for extracting high-temperature data on liquids and the preparation of undercooled liquid samples are presented. Properties of a well-determined substance, B-2 O-3, including the glass transition, are then discussed in detail to emphasize specific modelling requirements for the liquid. We then examine the two-state model proposed for CALPHAD in detail and compare results with experiment and theory, where available. We further examine the contributions of atomic-scale methods to the understanding of liquids and their potential for supplementing available data. We discuss molecular dynamics (MD) and Monte Carlo methods that employ atomic interactions from classical interatomic potentials, as well as contributions from ab initio MD. We conclude with a summary of our findings.
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| 2. |
- Rogal, Jutta, et al.
(författare)
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Perspectives on point defect thermodynamics
- 2014
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Ingår i: Physica status solidi. B, Basic research. - : Wiley. - 0370-1972 .- 1521-3951. ; 251:1, s. 97-129
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Tidskriftsartikel (refereegranskat)abstract
- We review and discuss methods for including the role of point defects in calculations of the free energy, composition and phase stability of elements and compounds. Our principle aim is to explain and to reconcile, with examples, the perspectives on this problem that are often strikingly different between exponents of CALPHAD, and others working in the overlapping fields of physics, chemistry and materials science. Current methodologies described here include the compound energy formalism of CALPHAD, besides the rather different but related canonical and grand-canonical formalisms. We show how the calculation of appropriate defect formation energies should be formulated, how they are included in the different formalisms and in turn how these yield equilibrium defect concentrations and their contribution to free energies and chemical potentials. Furthermore, we briefly review the current state-of-the-art and challenges in determining point defect properties from first-principles calculations as well as from experimental measurements.
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