A new model of grain-boundary segregation with the formation of atomic complexes in a grain boundary

Abstract

The process of grain-boundary segregation (GBS) has been considered under an assumption that the formation of associates (atomic complexes with a composition that corresponds to the nearest chemical composition in the phase diagram) is possible in a grain boundary (GB). The grain boundary is considered as a two-component mixture of A and B atoms, which can exist both in free and bound states (bound in a complex). The formation of complexes with an arbitrary composition and complexes of an AB type have been considered. It has been shown that, even in the absence of segregation (b = 1), the interactions of atoms in a GB that induce the formation of complexes leads to an enrichment of GBs in impurity atoms. It has been demonstrated that under certain conditions, a GBS isotherm can exhibit saturation corresponding to the chemical composition of the complex.