Molecular-dynamics study of partial edge dislocations in copper and gold: Interactions, structures, and self-diffusion

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© 1996 American Physical Society (APS). This is the accepted version of the following article: von Boehm, Juhani & Nieminen, Risto M. 1996. Molecular-dynamics study of partial edge dislocations in copper and gold: Interactions, structures, and self-diffusion. Physical Review B. Volume 53, Issue 14. 8956-8966. ISSN 1550-235X (electronic). DOI: 10.1103/physrevb.53.8956, which has been published in final form at http://journals.aps.org/prb/abstract/10.1103/PhysRevB.53.8956.
Journal Title
Journal ISSN
Volume Title
School of Science | A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä
Date
1996
Major/Subject
Mcode
Degree programme
Language
en
Pages
8956-8966
Series
Physical Review B, Volume 53, Issue 14
Abstract
The interactions between the [112] partial dislocations (PD), the interactions of vacancies and interstitials with the PD and their structures near the PD, as well as self-diffusion along the PD's in copper and gold are studied by using constant-NTV (number of atoms, temperature, and volume) molecular dynamics and the Ackland-Tichy-Vitek-Finnis many-atom interaction model. The interaction energy between the PD's is found to agree accurately with the elastic-continuum energy beyond and at the equilibrium separation distance whereas the former energy grows much more strongly at smaller separation distances due to the increased core repulsion. This behavior indicates a small core overlap at the equilibrium. A vacancy at the edge of a PD is found to have a form of a distorted hexagon whereas an interstitial is found to form a long ⟨110⟩ crowdion in the (111¯) plane in front of the edge of a PD for both metals. The self-diffusion activation energy for the vacancy mechanism is found to be at least 0.33 eV smaller than that for the interstitial mechanism in the region of the PD pair in gold whereas the corresponding activation energies are estimated to be equal in copper. We find that self-diffusion has nearly equal components along the edges of the PD's and the stacking fault ribbon. This can explain why self-diffusion in metals has a tendency to be weaker along PD pairs than along perfect dislocations.
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Keywords
molecular dynamics, dislocations, copper, gold, interactions, structures, diffusion
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Citation
von Boehm, Juhani & Nieminen, Risto M. 1996. Molecular-dynamics study of partial edge dislocations in copper and gold: Interactions, structures, and self-diffusion. Physical Review B. Volume 53, Issue 14. 8956-8966. ISSN 1550-235X (electronic). DOI: 10.1103/physrevb.53.8956.