Dresden 2014 – scientific programme

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MM: Fachverband Metall- und Materialphysik

MM 18: Poster Session

MM 18.26: Poster

Monday, March 31, 2014, 18:00–20:00, P4

C, N and H binding energies in Fe2Nb Laves — •Alvin Noe Ladines, Thomas Hammerschmidt, and Ralf Drautz — ICAMS, Ruhr Universität Bochum, Germany

The family of Laves phases are interesting from a technological point of view because of their capability for hydrogen storage and their strengthening effect in steel. Although their bulk properties are well understood, the solubility of light elements in these compounds is still unclear. This is due in part to their complex defect structure and the limitations of current experimental techniques for light elements. In this study, we use density functional theory (DFT) to calculate the solubility of C, N and H at the different interstitial sites in the Fe₂Nb C14 Laves phase. Our results suggest that the light elements prefer the voids centered at the triangles shared by two adjacent tetrahedral elements over the centers of these tetrahedra due to the slightly larger volume. Moreover, the binding energies are also dependent on the number of Nb nearest neighbors which is consistent with the high affinity of C, N and H to Nb. Our results suggest a considerable solubility of N and H in Fe₂Nb. For C, we observe a weaker solubility which we attribute to the increased strain that is apparent as increased bond lengths.