Statistical calculations of tracer and intrinsic diffusion coefficients in concentrated alloys and estimates of microscopic parameters of diffusion from experimental data

Abstract

The earlier-developed statistical theory of diffusion in concentrated alloys based on the master equation approach is generalized to treat tracer diffusion in binary alloys. The theory developed is used to describe concentration dependencies of both tracer and intrinsic diffusion coefficients and to estimate microscopic parameters of diffusion in alloys CuNi, CuZn and AgCd for which necessary experimental data are available. We show that all main features of strong and peculiar concentration dependencies of diffusion coefficients observed in these alloys are naturally explained by the theory. Signs and scales of interatomic interactions important for diffusion in these alloys are found to strongly depend on the ratio of atomic sizes of alloy components, and types of these dependencies agree with simple physical considerations. We also discuss physical reasons for sharp concentration dependencies of diffusion coefficients characteristic of real alloys.

Keywords:

• tracer and intrinsic diffusion
• statistical theory
• interatomic interactions
• vacancies
• concentration dependencies

Notes

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported in part by the Russian Fund of Basic Research [grants number 12-02-00093], [grant number 15-02-02084-a]; and by the fund for support of leading scientific schools of Russia [grant number NS-215.2012.2], [grant number NS-932.2014.2]. The results of the work were obtained using computational resources of MCC NRC “Kurchatov Institute” (http://computing.kiae.ru/).