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arXiv · 2409.18864

Nonequilibrium thermodynamic foundation of the grand-potential phase field model

Jin Zhang·James A. Warren·Peter W. Voorhees
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Abstract

Choosing the correct free energy functional is critical when developing thermodynamically consistent phase field models. We show that the grand-potential phase field model minimizes the Helmholtz free energy when mass conservation is imposed. While both functionals are at a minimum at equilibrium, the Helmholtz free energy decreases monotonically with time in the grand-potential phase field model, whereas the grand potential does not. Minimizing the grand potential implies a different problem where a system can exchange mass with its surroundings at every point, leading to a condition of isochemical potential and invalidating mass conservation of the system.

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Jin Zhang, James A. Warren, Peter W. Voorhees. 2024-09-27. Nonequilibrium thermodynamic foundation of the grand-potential phase field model. https://doi.org/10.1103/physreve.111.l022104

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