Vliv segregovaných nemagnetických sp-nečistot na vlastnosti hranic zrn a povrchů v niklu
| Title in English | Effect of segregated nonmagnetic sp-impurities on the properties of grain boundaries and surfaces in nickel |
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| Authors | |
| Year of publication | 2011 |
| Type | Article in Proceedings |
| Conference | Sborník doktorské konference: Víceúrovňový design pokrokových materiálů |
| MU Faculty or unit | |
| Citation | |
| Field | Solid matter physics and magnetism |
| Keywords | grain boundary segregation nickel |
| Description | We present an ab initio study of segregation of 12 nonmagnetic sp impurities (Al, Si, P, S, Ga, Ge, As, Se, In, Sn, Sb and Te) at the Sigma5(210) grain boundary (GB) and (210) free surface (FS) in fcc ferromagnetic nickel and analyze their effect on structure, magnetic and mechanical properties. We determine the preferred segregation sites of the impurity atoms, their segregation enthalpies and strengthening/embrittling energies with their decomposition into the chemical and mechanical components. We find that the value of mechanical component is dependent on the type of the stable segregation position and is nearly constant in each period. On the other hand the chemical component changes strongly within each period and is determined by the electronegativity of impurity atoms. Magnetically dead layers found at the impurity segregated GB and FS are caused by a strong hybridization of sp states of the impurities with the d states of nickel. |
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