Atomistic simulations of mobile defect clusters in metals
The structure, stability and thermally-activated motion of interstitial and vacancy clusters in Fe and Cu have been studied using atomic scale computer simulation. All studied interstitial clusters and perfect interstitial loops (PILs) in Fe are mobile whereas their mobility in Cu can be suppressed at large sizes (bigger than 49--61 self-interstitials depending on the temperature) due to dissociation. A comparative study of relaxed configurations has shown that the structure of small perfect dislocation loops of vacancy and self-interstitial nature is very similar. Molecular dynamics simulation has demonstrated that small perfect vacancy loops (PVLs) in Fe consisting of more than 37 vacancies are stable over a wide temperature range and produce atomic displacements by a thermally-activated movement in the direction of the Burgers vector. The mechanism is qualitatively similar to that of SIA clusters studied earlier. Motion of vacancy loops in Cu does not occur because they transform into sessile configurations similar to stacking fault tetrahedra. These results point to the possibly important contribution of vacancy loop mobility to the difference in radiation damage between bcc and fcc metals, and between fcc metals with different stacking fault energy.
- Research Organization:
- Univ. of Liverpool (GB)
- Sponsoring Organization:
- UK Engineering and Physical Sciences Research Council
- OSTI ID:
- 20014982
- Resource Relation:
- Conference: Multiscale Modeling of Materials, Boston, MA (US), 11/30/1998--12/03/1998; Other Information: Single article reprints are available through University Microfilms Inc., 300 North Zeeb Rd., Ann Arbor, Michigan 48106 (US); PBD: 1999; Related Information: In: Multiscale modeling of materials. Materials Research Society symposium proceedings: Volume 538, by Bulatov, V.V.; Diaz de la Rubia, T.; Phillips, R.; Kaxiras, E.; Ghoniem, N. [eds.], 607 pages.
- Country of Publication:
- United States
- Language:
- English
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