Dresden 2009 – wissenschaftliches Programm

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MM: Fachverband Metall- und Materialphysik

MM 27: Interfaces I

MM 27.1: Vortrag

Mittwoch, 25. März 2009, 11:30–11:45, IFW B

Grain boundary migration by molecular-dynamics simulation — •Jian Zhou, Volker Mohles, and Günter Gottstein — Institut für Metallkunde und Metallphysik, RWTH Aachen, Aachen

Molecular dynamics simulations have been used to study grain-boundary migration of three series ([001], [011], [111]) of twist grain boundaries (GBs) in copper. An orientation-correlated force being able to drive flat GBs with different misorientations was applied to all twist GBs. The temperature dependence of the GB mobility was determined over a wide misorientation range. It is found that there is an obvious reduction in activation enthalpy with respect to GB migration when the temperature rises to a certain point for many high-angle and high-energy GBs. This reduction could be attributed to the structural change in GBs, such that different GB migration mechanisms become active. Moreover, GB structures were characterized by common neighbor analysis at low temperature. For low-angle GBs, a network of screw dislocations were traced, and it was found that this structure is relatively stable during the GB migration process. For high-angle GBs, in contrast, much more complicated and spatially extended GB structures were observed, which move mainly by a collective shuffle mechanism.