Dresden 2009 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 48: Nanostructured Materials IV

MM 48.6: Talk

Friday, March 27, 2009, 11:30–11:45, IFW B

Plasticity in Nanocrystalline Tungsten — •Jonathan Schäfer and Karsten Albe — Institut f. Materialwissenschaft, TU Darmstadt, Petersenstr. 23, D-64287 Darmstadt

Computational simulation methods such as the molecular dynamics method are very useful to gain more insights into the deformation mechanisms of nanocrystalline materials. Especially for the class of fcc metals a lot of simulations have been carried out in the past in order to investigate dislocation emission, grain boundary sliding, and other processes on the atomic level. For the class of bcc materials, however, a complete map of deformation mechanisms is still missing and supposed mechanisms like the formation of cracks at the grain boundaries have not been confirmed yet. Tungsten as a bcc model material is of particular interest because its melting point, which is higher than for any fcc material, might permit the observation of thermally activated processes during deformation at elevated temperatures. We present Molecular Dynamics simulations of nanocrystalline Tungsten model structures generated using the Voronoi method. Deformation experiments are carried out at different temperatures and various loading conditions. The role of the interatomic potential (Analytic bond order potential, Finnis-Sinclair potential) and the influence of the structure synthesis method on the mechanical behavior are assessed. Additionally, mechanisms like crack formation at grain boundaries are addressed.