Diffusion by the Vacancy Mechanism in the Materials with the Large Number of Internal Surfaces
A. G. KNYAZEVA
Institute of Strength Physics and Materials Science,
Siberian Branch of the Russian Academy of Sciences,
Pr. Akademicheskiy 2/1, Tomsk 634021 (Russia) E-mail: anna@ms.tsc.ru
Pages: 233-242
Abstract
The relationships for irreversible flows of matter, vacancies, surfaces, and heat are derived with the allowance for various cross effects on the basis of the model of a medium with additional parameters that determine structural features and availability of vacancies and internal surfaces. The generalized linearized relationships for the rates of chemical reactions, for the sources of vacancies and surfaces, as well as a generalization of the law of internal friction have been obtained. Analysis of various types of diffusive flows has been conducted for the diffusion that proceeds through the replacement mechanism. It was revealed, in particular, that the coefficient of volumetric diffusion in a polycrystalline material is other than the coefficient of self-diffusion for a single crystal that should be taken into account when interpreting experimental data for diffusion in fine structured materials.
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