Regensburg 2010 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 13: Topical Session Designing Innovative Structural Materials and Steels IV

MM 13.1: Talk

Monday, March 22, 2010, 16:00–16:15, H4

Atomic-scale quantification of the mechanisms underlying solid solution hardening — •Johann von Pezold, Martin Friák, and Jörg Neugebauer — Max-Planck-Institut für Eisenforschung GmbH, Max-Planck Strasse 1, 40237 Düsseldorf

The increase in the initial flow stress of metals by the introduction of impurity atoms (solid solution hardening) is generally accounted for by a combination of the size (parelastic) and elastic (dielastic) mismatch between the host and the solute atoms. In this study we have investigated the mobility of edge dislocations in aluminum in the presence of impurity atoms using Molecular Dynamics (MD) simulations in order to quantify the relative contributions of the two effects. The Al host was described by an embedded-atom-type potential (EAM), while the impurity atoms were introduced by overlaying the EAM potential with a Lennard-Jones potential on the impurity sites, which allowed us to independently vary the size- and elastic mismatch between the metal host and the defect atoms. Our results suggest that the size mismatch is the predominant contribution to solid solution hardening, while the dielastic interaction is only of secondary importance. Based on this insight we discuss a multiscale approach for the determination of optimum hardening conditions from ab initio calculations.