From wetting to melting along grain boundaries using phase field and sharp interface methods
V. Sai Pavan Kumar Bhogireddy, C. Hueter, J. Neugebauer, O. Shchyglo, I. Steinbach, R. Spatschek,
Volume: 108. Pages: 293--300
DOI: 10.1016/j.commatsci.2015.02.040
Published: #oct# 2015
Abstract
We investigate the ability of a multi-order parameter phase field
model with obstacle potentials to describe grain boundary premelting
in equilibrium situations. In agreement with an energetic picture
we find that the transition between dry and wet grain boundaries
at the bulk melting point is given by the threshold 2 sigma(sl) -
sigma(gb), with sigma(sl) being the solid-melt interfacial energy
and sigma(gb) the energy of a dry grain boundary. The predictions
for premelting are confirmed by simulations using the phase field
package OPENPHASE. For the prediction of the kinetics of melting
along grain boundaries in pure materials, taking into account the
short ranged interactions which are responsible for the grain boundary
premelting, a sharp interface theory is developed. It confirms that
for overheated grain boundaries the melting velocity is reduced (increased)
for non-wetting (wetting) grain boundaries. Numerical steady state
predictions are in agreement with a fully analytical solution in
a subset of the parameter space. Phase field simulations confirm
the predictions of the sharp interface theory. (C) 2015 Elsevier
B.V. All rights reserved.