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Mikhail D. Starostenkov ,  Gennady M. Poletaev ,  Roman Y. Rakitin 

Altai State Technical University (ASTU), Lenin st.46, Barnaul 656038, Russian Federation


The present paper is concerned with the research of diffusion mechanism at the grain boundaries in two-dimensional metals by the method of molecular dynamics. The diffusion of atoms was studied on the example of three metals: Ni, Al, Cu. The packing of two-dimensional crystals was corresponded to the plane [111] of FCC lattice. To describe interatomic interactions, pair Morse potentials were used. The metals under study were heated up to the temperatures, corresponded to 0.3 - 0.95 relatively to the melting temperature. Severe boundary constraints were applied on the boundaries of the calculated block.
It was found, that leading diffusion mechanism at the grain boundaries of two-dimensional metals was the result of interaction of grain boundary dislocation pairs. The creep of dislocation pairs in opposite sides was observed in the experiments. The rugged atomic row of one dislocation was lengthened at the expense of shortening of the other dislocation atomic row. In this connection, the chain of the displaced atoms was observed in the directions, connecting the nuclei of two dislocations. The inverse displacements of atoms ? the return of atoms in the initial positions, were observed. One of the important elements of similar mechanism is the appearance of the vacancy in the chains of the displaced atoms. The vacancy is the additional intensificating factor of diffusion. The trajectory of the vacancy migration from one nucleu to the other one can have ring reserved elements, which are the cause of the appearance of ring exchange displacements of atoms at the boundary. The research showed, that the stresses, causing the migration of the boundary, temperature and density of grain boundary dislocations influence greatly on the diffusion velocity.


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Presentation: oral at E-MRS Fall Meeting 2004, Symposium H, by Mikhail D. Starostenkov
See On-line Journal of E-MRS Fall Meeting 2004

Submitted: 2004-04-13 10:47
Revised:   2009-06-08 12:55