MODELLING OF PHASE FORMATION IN SOLID-SOLID AND SOLID-LIQUID INTERACTIONS: NEW DEVELOPMENTS

Recent developments (after 2016) in modelling of phase formation during solid-solid and solid-liquid reactions by SKMF (Stochastic Kinetic Mean-Field) method, Monte Carlo simulation and phenomenological modelling are reviewed. Reasonable results of multiphase reactive diffusion modelling demonstrating distinct concentration plateau for each intermediate ordered compound and distinct concentration steps between these phases are obtained by the SKMF and Monte Carlo methods, if one takes into account interatomic interactions within two coordination shells and if the signs of mixing energies are 'minus' for the first coordination shell and 'plus' for the second one. Second possibility for reasonable modelling results is consideration of interatomic interactions depending on local concentration with maxima around stoichiometric composition. In phenomenological modelling, the generalization of Wagner diffusivity concept and respective superposition rule are introduced. New mechanism of the lateral grain growth in the growing phase layers during reactive diffusion is suggested. Anomalously fast grain growth at the final stages of soldering in sandwich-like Cu-Sn-Cu contacts is reported and explained. Simple model of Zn-additions' influence on the Cu-Sn reaction is described.