Role of nonequilibrium vacancies at interdiffusion in a crystal without sinks

О. М. Rymar, А. М. Gusak

Abstract


For the first time the results of interdiffusion n simulation in fcc structure between pure components A and B by the kinetic mean-field method are presented. Nonequilibrium vacancies redistribution is taken into account in the system. Initial distribution of the components with average concentration 0.5 is chosen to be sinusoidal. Initial vacancy concentration is chosen to be constant. From the beginning, we have a concentration gradient of A and B. Concentration profiles evolution at various combinations of pair interaction energies is studied. In case of equal frequency factors of the components , the vacancy concentration remains constant everywhere. If frequency factors are not the same, the distribution of vacancies becomes sinusoidal. At the same time, vacancies start to accumulate on the side of material with lower melting point. In the symmetric case ( the same energy values of pairwise interactions A-A and B-B ) there occurs the formation of an ordered phase AB. The formation of an ordered phase AB also has been observed after introduction of asymmetry to the system but with asymmetric nature of the redistribution of vacancies.


Keywords


Kinetic mean-field method; mutual diffusion; nonequilibrium vacancies; asymmetry

References


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