Regensburg 2022 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 6: Computational Materials Modelling: Defects / Alloys

MM 6.2: Talk

Monday, September 5, 2022, 16:00–16:15, H44

Macroscopic characteristics of plastic deformation described through dislocation mobility properties — •Sergei Starikov, Antoine Kraych, and Matous Mrovec — Ruhr University Bochum, ICAMS, Germany

Plastic deformation of bcc metals is a complicated phenomenon that links a behaviour of crystal defects with the macroscopic change of a sample shape. It is known that one of the basic mechanisms of plasticity is a motion of dislocations under applied stress. In this work, on the example of Mo and Nb, the study of plastic deformation in bcc metals was carried out with large-scale atomistic modelling. The temperature-dependent mobility functions of screw and edge dislocations were calculated from molecular dynamics simulation. The simulations of screw dislocation movement under applied shear stress revealed that the process can proceed in two different regimes: through thermally activated motion and athermal motion. Hence, the dislocation velocity depends on the shear stress in a non-trivial way. The calculated data provide a way to evaluate the basic macroscopic characteristics of plastic deformation at various temperatures and strain rates.