Kinetic behaviour of vacancies and atoms in binary alloys

Abstract

With the introduction of the two-particle distribution function a set of simultaneous rate equations is derived which describes the time dependence of the vacancy concentration as well as the arrangement of atoms and vacancies in binary alloys. The model takes into account the exchange of sites between atoms and vacancies with a jump rate that depends only on their immediate environment. The general theory thus developed, which includes as a special case tho state of thermal equilibrium, is applied to α Cu‒Al alloys with various compositions, and can reproduce satisfactorily the temperature dependence of the self-diffusion coefficient of Cu and Al atoms in these alloys. Furthermore, these equations account for the observed kinetic behaviour of their physical properties, such as the specific heat and electrical resistivity.