Regensburg 2013 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 22: Computational Materials Modelling - Phase Stability II

MM 22.5: Talk

Tuesday, March 12, 2013, 12:45–13:00, H24

Comparison of Analytic and Numerical Bond-Order Potentials for bcc Refractory Metals — •Miroslav Cak, Thomas Hammerschmidt, and Ralf Drautz — ICAMS, Ruhr-Universität Bochum, Germany

A systematic coarse-graining of the electronic structure leads from DFT to tight-binding and to bond-order potentials (BOP). The calculation of the total energy of a system of interacting atoms can be carried out within the formalism of either analytic or numerical BOP. Recently, we developed parameterizations of analytic BOPs for the refractory metals Tungsten, Molybdenum, Niobium and Tantalum. These refractory metals play an important role as strengtheners of nickel- and cobalt-based superalloys. Here we employ our new parameterizations in a detailed comparison of numerical and analytic BOP and find very good agreement for various bonding configurations. Comparing these BOP calculations to corresponding first-principles, tight-binding and experimental results confirms the transferability of both BOP schemes to atomic structures encountered in lattice defects. As an application of our BOPs we determine the interaction of dislocations with other defects like vacancies.