Microscopical derivation of Ginzburg-Landau-type functionals for alloys and their application to studies of antiphase and interphase boundaries

摘要

The earlier-described cluster methods are used to generalize theGinzburg-Landau gradient expansion for the free energy of an inhomogeneousalloy to the case of not small values of order parameters and variations ofcomposition. The results obtained reveale a number of important differenceswith the expressions used in the phenomenological phase-field approach.Differential equations relating the local values of concentration and orderparameters within the antiphase or interphase boundary (APB or IPB) arederived. These equations are applied to study the segregation at APBs near thephase transition lines; the structure of APBs and IPBs near tricritical points; pre-wetting and wetting APBs in phaseswith single and several order parameters; and also some effects of anisotropyof APBs under L1$_0$ and L1$_2$-type orderings.