Dresden 2014 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 49: Computational Materials Modelling VII - Grain boundaries & Interfaces
MM 49.5: Vortrag
Donnerstag, 3. April 2014, 11:15–11:30, IFW D
Atomistic simulation of a severe plastic deformation-induced "high-energy" state of grain boundaries — •Lisa Neier1, Sergiy Divinski1, Anantha Padmanabhan2, and Gerhard Wilde1 — 1Institut für Materialphysik, Westfälische-Wilhelms-Universität, 48149 Münster — 2University of Hyderabad, India
A comparison of microstructures and properties in materials subjected to the later stages of severe plastic deformation or steady-state superplastic flow indicates several unexpected similarities especially with respect to the interface response on the deformation, such as grain boundary (GB) sliding events, which lead to a suppression of dislocation activity. Making use of this idea, we propose to describe the experimentally observed "high-energy" (or "non-equilibrium") state of general high-angle GBs in SPD-processed materials in terms of the concept of shear localization in the interfaces and choosing oblate spheroids of a few atomic diameters size as the basic units of sliding. Atomistic simulations of these special GBs are performed. The coupling of grain boundary motion in normal direction to a shear deformation parallel to the grain boundary plane is investigated for these special grain boundaries in comparison to those of different relaxed high angle grain boundaries. Furthermore thermal equilibrium fluctuations of the grain boundaries during the MD simulations are used to calculate the grain boundary stiffness and analyze the influence of grain boundary structure and shear localization on the fluctuation spectrum.