Comments on the paper of V. L. Gapontsev and V. M. Koloskov “Nonequilibrium vacancy-stimulated diffusion (induced diffusion) as the main mechanism of activated alloy formation”

Abstract

The authors of the considered paper in their study are focusing on systems of metal phases that can be called substitution phases. Presumably, in this case a variation of the mixture composition in the course of reaction is of less significance, since here in diffusion we observe point defects of the same sort (vacancies). It would be interesting to investigate the diffusion of interstitial atoms for some real objects. Due to the low values of diffusion activation energy for interstitial atoms, we could expect an improved sensitivity of the methods to composition variation (a higher diffusion coefficient). In any case it appears necessary to discuss the role of interstitial atoms in the preservation of the vacancy concentration with respect to annihilation processes. It follows from the theory proposed by V. Indenbom and A. Orlov that plastic deformation under low temperatures and significant loads, which are typical for high-energy mills, leads to the formation of interstitial atoms. The considered paper gives several examples of the practical use of mechanochemical synthesis. It would be important for the description of particular examples to include all parameters of synthesis, as well as selection, calculation of quantities, and methods of introduction of material, in particular, for so-called nonequilibrium vacancies. Below are certain considerations regarding the state of an activated alloy.