A comparison of Redlich-Kister polynomial and cubic spline representations of the chemical potential in phase field computations
| Autor: | Anirudh Raju Natarajan, Krishna Garikipati, Brian Puchala, Gregory H. Teichert, Shiva Rudraraju, N. S. Harsha Gunda, Anton Van der Ven |
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| Rok vydání: | 2017 |
| Předmět: |
Polynomial
Phase transition General Computer Science Spinodal decomposition FOS: Physical sciences General Physics and Astronomy 02 engineering and technology 01 natural sciences 0103 physical sciences General Materials Science Statistical physics Free energy Second derivative 010302 applied physics Condensed Matter - Materials Science Partial differential equation Numerical analysis Materials Science (cond-mat.mtrl-sci) General Chemistry Statistical mechanics Phase transformation 021001 nanoscience & nanotechnology Computational Mathematics Spline (mathematics) Mechanics of Materials 0210 nano-technology |
| Zdroj: | Computational Materials Science. 128:127-139 |
| ISSN: | 0927-0256 |
| DOI: | 10.1016/j.commatsci.2016.11.024 |
| Popis: | Free energies play a central role in many descriptions of equilibrium and non-equilibrium properties of solids. Continuum partial differential equations (PDEs) of atomic transport, phase transformations and mechanics often rely on first and second derivatives of a free energy function. The stability, accuracy and robustness of numerical methods to solve these PDEs are sensitive to the particular functional representations of the free energy. In this communication we investigate the influence of different representations of thermodynamic data on phase field computations of diffusion and two-phase reactions in the solid state. First-principles statistical mechanics methods were used to generate realistic free energy data for HCP titanium with interstitially dissolved oxygen. While Redlich-Kister polynomials have formed the mainstay of thermodynamic descriptions of multi-component solids, they require high order terms to fit oscillations in chemical potentials around phase transitions. Here, we demonstrate that high fidelity fits to rapidly fluctuating free energy functions are obtained with spline functions. Spline functions that are many degrees lower than Redlich-Kister polynomials provide equal or superior fits to chemical potential data and, when used in phase field computations, result in solution times approaching an order of magnitude speed up relative to the use of Redlich-Kister polynomials. |
| Databáze: | OpenAIRE |
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