Microscopical derivation of Ginzburg-Landau-type functionals for alloys and their application to studies of antiphase and interphase boundaries
V. G. Vaks
Russian Research Centre "Kurchatov Institute", 123182 Moscow, Russia
PACS: 05.70.Fh, 61.50.Ks
Abstract
The earlier-described cluster methods are used to generalize the
Ginzburg-Landau gradient expansion for the free energy of an inhomogeneous
alloy to the case of not small values of order parameters and variations of
composition. The results obtained reveale a number of important differences
with the expressions used in the phenomenological phase-field approach.
Differential equations relating the local values of
concentration and order parameters within the antiphase or interphase boundary
(APB or IPB) are derived. These equations are applied to study
the segregation at APBs near the phase transition lines; the structure of
APBs and IPBs near tricritical points;
wetting APBs in phases with single and several order parameters;
and also some effects of anisotropy of APBs under L10 and L12-type
orderings.