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Molecular dynamics simulation of defect formation in irradiated face centered cubic materials

D. ŞOPU1, D. M. POPOVICI2, M. A. GÎRŢU1,*

Affiliation

  1. Department of Physics, Ovidius University of Constanţa, Constanţa, 900527, Romania
  2. Department of Mathematics and Computer Science, Ovidius University of Constanţa, Constanţa, 900527, Romania

Abstract

There are presented molecular dynamics simulations of collision cascades in various metals (Al, Cu, Ni, Pb) irradiated with ions of up to 1000 eV kinetic energy, with the aim of studying the degradation of the physical properties of some face centered cubic metallic materials used in nuclear power plants. We simulated systems of up to 37000 atoms using periodic boundary conditions only along the transverse directions, perpendicular to the direction of the initial impact. We kept the system at constant temperature, and performed multiple runs, changing slightly and randomly the direction of the projectile ion. We studied the time evolution of the defects induced by irradiation and we analyzed various numbers of multiple vacancies (mono-, di-, tri-, and tetra- vacancies). We find that, for all materials, although during the collision cascade, due to local melting, some regions of the sample become amorphous, during the relaxation phase the atoms tend to return to their equilibrium positions and the systems recrystallize. The smallest number of defects and the fastest recrystallization was observed in the case of Ni. The largest path through the target and number of defects was seen for Al, while the slowest lattice relaxation regeneration was found for Pb..

Keywords

Ion irradiation, Collision cascades, Thermal spike, Local melting, Frenkel defects, Recrystallization, Fcc metals.

Submitted at: Nov. 2, 2006
Accepted at: April 15, 2007

Citation

D. ŞOPU, D. M. POPOVICI, M. A. GÎRŢU, Molecular dynamics simulation of defect formation in irradiated face centered cubic materials, Journal of Optoelectronics and Advanced Materials Vol. 9, Iss. 4, pp. 799-809 (2007)