New coarse-grained derivation of a phase field model for precipitation.
We present the first derivation of the phase field equations using a coarse-graining procedure on a microscopic master equation. The procedure leads to a mesoscopic nonlinear Fokker-Planck equation equivalent to a Cahn-Hilliard equation supplemented with a noise, but with specific prescriptions for the mobilities and the noise term. All the ingredients (chemical potentials, mobilities, stiffness coefficient) depend on the coarse-graining size. Finally, we show the ability of the phase field equations to describe a precipitation kinetics involving a nucleation and growth mechanism.
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Laboratoire d'Etude des Microstructures, ONERA-CNRS 29, avenue de la Division Leclerc BP 72, 92322 Chatillon Cedex, France.
Le Bouar
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Finel
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