Papers by Author: I.V. Nelasov

Abstract: Titanium additions suppress the radiation swelling in vanadium alloys, but the mechanism of the suppression is debatable. It is claimed that interactions of Ti atoms with vacancies in vanadium are crucial in the suppression. In this paper we study clustering of excess vacancies in pure V and V-4Ti by molecular dynamics simulations at 700 K based on our interatomic potentials constructed earlier for the Ti-V system. For pure V the process results in the formation of a Frank sessile dislocation while the clustering in V-4Ti ends with the formation of the Ti-vacancies complexes with a specific structure. This allows us to discuss a possible mechanism of the swelling reduction in V caused by Ti alloying.

Abstract: Suggested methods describe the process of self-diffusion along grain boundaries and triple junctions in polycrystals without using geometric models of the grain boundaries structure. The calculation method introduced diffusion characteristics along grain boundaries derived from the results of molecular dynamic simulations of nanocrystalline materials. The diffusion experiments were imposed to establish relationship between introduced diffusion characteristics and the diffusion parameters along grain boundaries and triple junctions of the Fisher’s grain boundary diffusion model. By the example of copper for the first time the characteristics of self-diffusion along grain boundaries of nanocrystalline materials and coarse grained analog defined in the same temperature range was compared for the first time. It was found that values of the self-diffusion characteristics along grain boundaries in high purity nanocrystalline and polycrystalline copper are equal at the same temperatures.