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Atomistic modeling of the interaction between dislocation and vacancy in tungsten

: Chen, Z.; Mrovec, M.; Weygand, D.; Gumbsch, P.

El-Azab, A. ; Florida State University, Department of Scientific Computing:
MMM 2008, Fourth International Conference Multiscale Materials Modeling : October 27-31, 2008, Tallahassee, Florida, USA
Tallahassee, Fla., 2008
ISBN: 978-0-615-24781-6
International Conference on Multiscale Materials Modeling (MMM) <4, 2008, Tallahassee/Fla.>
Fraunhofer IWM ()

The interaction between the 1/2<111> screw dislocation and a vacancy in body-centred cubic (bbc) metal tungsten is studied by means of atomistic simulations. In order to investigate the influence of the vacancy on dislocation mobility, the Nudged Elastic Band method is implemented to determine the changes of the energy barrier for the dislocation motion. Our simulation results show that the dislocaton mobility may be strongly influenced by the presence of vacancies and the change of the energy barrier depends sensitively on the vacancy position. A comparison of the simulation results with predictions of the elasticity theory shows an excellent agreement between the two approaches wehen the separation between the vacancy and the dislocation core is larger than 1 nm but large deviation from the elastic limit when the vacancy approaches the dislocation core.