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The Formation of Aggregates from Ni Atoms at the Impulsive High-Intensive Influences on Ni3Al Intermetallide

Mikhail D. Starostenkov ,  Aleksandr V. Yashin ,  Olga A. Tereschenko ,  Olga V. Pozhidaeva ,  Nikolay N. Medvedev 

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

Abstract

The process of nanoclusters aggregatization containing of Ni atoms in the structure of Ni3Al intermetallide is studied in the present paper. The process takes place at the internal high-intensive influences-radiation and deformation ones. The researches were made by the method of molecular dynamics. The calculated block of crystal contained 2*10^5 atoms and it repeated outside the crystal block by the introduction of periodical boundary conditions. The temporary step of re-calculation of the system of the movement equation was equal to 5*10^(-15) s. The temperature was given by the initial velocities in correspondence with Maxwell distribution. The directions of initial velocities were given randomly, but the total impulse of the atoms of the calculated block was given to zero. Simulation the radiation influence in the calculated crystal block, the definite number of Frenckel pairs – vacancies and interstitial atoms was introduced. But condition had to be fulfilled: stoichiometry of intermetallide composition. The formation and accumulation of Frenckel pairs took place at the definite levels and the velocities of an impulsive deformation of tension in the material. Such pairs recombined partially, the left pairs could unite into the aggregates in the migration process. The vacancies and interstitial atoms begin to form the aggregates such as flat accumulations in a form of dislocation loops volume crowdion complexes and tetrahedrons of fault defects at high concentrations of point defects. It was found that Ni atoms having less effective sizes in comparison with Al atoms tended to the formation of the above presented complexes Al atoms recombined on the structural vacancies as less mobile one. The intensivity of similar processes increases with the increase of temperature value and velocity of an impulsive deforming loading and duration of a computer experiment.

 

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Presentation: Poster at E-MRS Fall Meeting 2008, Symposium G, by Mikhail D. Starostenkov
See On-line Journal of E-MRS Fall Meeting 2008

Submitted: 2008-05-19 12:00
Revised:   2009-06-07 00:48