Regensburg 2016 – wissenschaftliches Programm
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MM: Fachverband Metall- und Materialphysik
MM 50: Methods in Computational Materials Modelling II: Microstructure evolution
MM 50.5: Vortrag
Donnerstag, 10. März 2016, 11:15–11:30, H53
Impurity diffusion in bcc-iron from first-principles — •Casper Versteylen1 and Marcel Sluiter2 — 1Mekelweg 2, 2628 CD Delft, the Netherlands — 2Mekelweg 15, 2629 JB Delft, the Netherlands
Since detailed knowledge of impurity diffusivities is vital in the design of new steel compositions and microstructures, substitutional diffusion in bcc-iron has been studied comprehensively. Calculating diffusivities at temperatures relevant for realistic applications is difficult for several reasons; accurate excess entropies must be determined for vacancy formation and element specific vacancy binding while accounting for magnetic disordering. Sophisticated techniques have been developed to evaluate the influence of magnetism on total energies, but to do so for a large number of impurity elements in iron is expensive. Therefore a method was developed that links first principles results to the semi-empirical Girifalco model. A general method to evaluate the influence of magnetic disordering on impurity diffusivities has been applied to 28 impurity elements in bcc-iron and to iron self-diffusion.