Dresden 2014 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 49: Computational Materials Modelling VII - Grain boundaries & Interfaces

MM 49.6: Vortrag

Donnerstag, 3. April 2014, 11:30–11:45, IFW D

Driving force and temperature dependence of grain boundary motion — •Christian Brandl¹, Danny Perez², Timothy C. Germann², and Oliver Kraft¹ — ¹Karlsruhe Institute of Technology, Institute of Applied Materials, Karlsruhe, Germany — ²Los Alamos National Laboratory, Theoretical Division, Los Alamos, USA

The motion of interfaces - in particular grain boundaries (GBs) - is a fundamental mechanism of microstructure formation at high temperature and long time scales (annealing, coarsening). Moreover GB motion is also shown to be a deformation mechanism occurring at high stresses and relative low temperatures as in deformation studies of nanocrystalline metals and shock loading. Using MD simulations and transition search methods (string method), we report on the interface motion of an asymmetric GB in Cu to elucidate the role of atomistic structure (morphology) and velocity-driving force relation (mobility) as function of temperature. We show that the GB velocity as a function of temperature and driving-force shows distinct regimes of dynamics regimes ranging from pinning-depinning transition at low temperature, through rare-event dynamics of critical kink-pair disconnection nucleation along intrinsic GB dislocations to approximate temperature independent GB velocities. We will discuss the observation in the context of necessary ingredients for a mesoscale model of interface motion, which incorporates the atomic scale interface structure and the different regimes of driving-force and temperature.