Papers by Author: V.L. Gapontsev

Abstract: The new way of calculation of segregation enthalpy on the basis of grain boundary diffusion data is offered. It proceeds from the primary data on an interval "B"- regime of grain boundary diffusion. For data processing we used the expression for coefficient of grain boundary diffusion got by Borisov and Lubov according to Fisher model for a tail part of the concentration curve. To approve this approach the data of tellurium diffusion in grain boundary of polycrystalline silver are considered.

Abstract: The problem of grain boundary diffusion for a case of boundary grain with periodic heterogeneity diffusion properties is considered. Dependence of Laplace transform images of impurity concentration on various diffusion conductivity places is built. The dimensionless parameters, forming the system of grain boundary diffusion regimes are determined. The space (ln x,lnt,1/T) is divided into areas in which the ratio ln ln ~ ln ln ( / ) ln eff o C r x−k t− Q RT − A is maintained, when the parameters of diffusion regime are constant. The values of parameters , , , eff o r k Q A fully specify the diffusion regimes. On this base the new concept for the definition of grain boundary diffusion regimes is carried out and the method for construction of simplified tracer concentration profile is proposed.