Regensburg 2019 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
MM: Fachverband Metall- und Materialphysik
MM 38: Methods in Computational Materials Modelling (methodological aspects, numerics)
MM 38.8: Vortrag
Donnerstag, 4. April 2019, 17:00–17:15, H44
Atomistic simulations of mixed 1/2 [111] dislocations in bcc transition metals — •Tapaswani Pradhan1, Anastasiia Kholtobina2, Lorenz Romaner3, Matous Mrovec4, and Ralf Drautz5 — 1Interdisciplinary Centre for Advanced Materials Simulation (ICAMS), Ruhr-Universität Bochum, Bochum, Germany — 2Materials Center Leoben Forschungs GmbH, Leoben, Austria — 3MCL Forschungs GmbH, Leoben, Austria — 4ICAMS, RUB, Bochum, Germany — 5ICAMS, RUB, Bochum, Germany
Structure and mobility of dislocations govern the mechanical properties of metals. It is widely accepted that in body-centered cubic (BCC) metals plastic deformation at low temperature is largely controlled by non-planar 1/2<111> screw dislocations. However, recently mixed 1/2<111> dislocations, which are predominantly of edge character and therefore expected to be glissile, were proposed to possess an unexpectedly high Peierls stress. In this study we investigate the core structures and mobilities of mixed 1/2<111> dislocations in five BCC transition elements Nb, Ta, Mo, W and Fe using atomistic simulations. The simulations were carried out with different models of interatomic interactions, ranging from classical potentials via tight-binding-based bond order potentials to first-principles methods based on density functional theory. Our study shows that both the predicted core structures and the Peierls barriers depend sensitively on the employed model and boundary conditions. We present a detailed comparison of different models and discuss the relation between atomic-scale properties and macroscopic behavior.