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M: Metallphysik

M 50: Grenzfl
ächen II

M 50.2: Vortrag

Dienstag, 8. März 2005, 16:45–17:00, TU H2038

Atomistic modelling of interactions between lattice dislocations and grain boundaries in body-centered cubic transition metals — •Matous Mrovec and Christian Elsässer — Fraunhofer-Institut für Werkstoffmechanik IWM, Wöhlerstr. 11, 79108 Freiburg

With grain sizes decreasing towards the nanometer scale, the plastic deformability of polycrystalline metals is increasingly controlled by interactions of lattice dislocations and grain boundaries. To elucidate such interactions at the atomic level, computer simulations were carried out for atomistic models of dislocations interacting with boundaries in body-centered cubic (bcc) transition metals. The interatomic interactions were described by bond-order potentials (BOP) derived from tight-binding electronic-structure theory [1]. These recently developed BOP have been applied already to simulate atomistic core structures of individual screw dislocations [2] and twin boundaries [3] in Mo, W and other bcc metals. In this contribution, BOP simulation results will be presented for atomistic structures and mechanical responses of W bicrystal models containing a twin boundary and a screw dislocation.

[1] M. Mrovec, Thesis, University of Pennsylvania (2002). [2] M. Mrovec et al., Phys. Rev. B 69 (2004) 095115. [3] T. Ochs et al., Phil. Mag. A 80, 2405 (2000).