Phenomenological theory of mass transfer in crystalline solid solutions is considered, taking into account the influence of mechanical stresses formed in the diffusion zone. The basic equations and formulas for description of stress-strain state and distribution of concentration in diffusion zone during mutual and reaction diffusion. are given. The most typical cases of diffusion interaction in bimetallic systems, as well as in oxidation, carbidization and nitriding of metals are analyzed. For scientific and engineering workers specializing in solid state physics and high temperature materials science . Table. 10. IL. 34. Bibliographic . 132.