| A simplified crystallization model is developed with emphasis on situations of disparate specific volumes of the solid and liquid phases. Using the general equation for the nonequilibrium reversible-irreversible coupling ( GENERIC), the model is formulated in terms of the average momentum density, the degree of crystallinity, a single temperature, and a single pressure, where in particular the latter two are appealing for comparison with experiments. In order to describe the volume expansion upon crystallization, a dissipative mass current density is introduced, for which a constitutive relation is derived. One finds that by way of the Onsager-Casimir symmetry, the introduction of this irreversible current also leads to a modi. cation of the driving force for phase change. Rather than depending only on the local chemical potential difference, it also contains a non-local term, namely the Laplacian of the ratio of pressure p to temperature T, multiplied by the square of a screening length. The model is studied for the specific case of aluminum, for which a perturbation analysis is performed. The results show that the type and rate of relaxation of a perturbation depend strongly on its wavelength and on the screening length.
for LaTeX users @article{MH\"utter2006-31,
author = {M. H\"utter},
title = {Volume change and non-local driving force in crystallization},
journal = {J. Non-Equilibrium Thermodyn.},
volume = {31},
pages = {73-101},
year = {2006}
}
\bibitem{MH\"utter2006-31} M. H\"utter,
Volume change and non-local driving force in crystallization,
J. Non-Equilibrium Thermodyn. {\bf 31} (2006) 73-101.MH\"utter2006-31
M. H\"utter
Volume change and non-local driving force in crystallization
J. Non-Equilibrium Thermodyn.,31,2006,73-101 |
mk@mat.ethz.ch
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