Regensburg 2010 – scientific programme
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O: Fachverband Oberflächenphysik
O 46: Density functional theory and beyond for real materials I
O 46.1: Talk
Wednesday, March 24, 2010, 10:30–10:45, H34
Structure and magnetism of clean and decorated grain boundaries in nickel — Monika Všianská1,2 and •Mojmír Šob1,2 — 1Department of Chemistry, Faculty of Science, Masaryk University, Brno, Czech Republic — 2Institute of Physics of Materials, Academy of Sciences of the Czech Republic, Brno, Czech Republic
With the help of density-functional theory, we have studied the structure and magnetism of the Σ5(210) grain boundary (GB) in nickel as well as segregation and embrittling potency of sp-elements in the 3rd, 4th and 5th period (Al, Si, P, S, Ga, Ge, As, Se, In, Sn, Sb and Te) at this GB. For comparison, segregation of these impurities at the (210) free surface (FS) has also been investigated. Full relaxation of the geometric configuration of the GB and FS without and with impurities has been performed and the effect of impurities on the distribution of magnetic moments has been analysed. We determined the embrittling potency energy from the difference between the GB and FS binding energies on the basis of the Rice-Wang model; here a positive/negative value of this quantity means that the solute atom has the embrittling/strengthening effect on the GB. It turns out that all substitutionally segregated impurities studied are GB embrittlers in Ni.