The diffusion mechanism in ordered systems should ensure the conservation of longrange order in the arrangement of atoms. However, despite the large number of theoretical and experimental papers devoted to this issue, the diffusion mechanisms in such systems havenot been established to date. Earlier in our works a variant of the mechanism is suggested that ensures the fulfillment of the above-mentioned condition, and the obtained barrier values for which are of lower values than other known mechanisms. In addition, it is noted in these papers that for a wide temperature range vacancies move in a tied state jumping on the different sublattices. Therefore, the bi-vacancy diffusion mechanism with jump atoms to vacancies from the second coordination sphere is considered.A model based on the Kinetic Monte Carlo and a set of programs for studying the migration of bivacancies and atoms in B2-type structures have been developed.

No abstract