Structure and magnetism of clean and impurity-decorated grain boundaries in nickel from first principles

0366272 - ÚFM 2012 RIV CZ eng K - Konferenční příspěvek (tuzemská konf.)
Všianská, Monika - Šob, Mojmír
Structure and magnetism of clean and impurity-decorated grain boundaries in nickel from first principles.
XI. Pracovního setkání fyzikálních chemiků a elektrochemiků. Brno: Mendelova zemědělská a lesnická univerzita, 2011 - (Trnková, L.), s. 74-77. ISBN 978-80-7375-514-0.
[Pracovní setkání fyzikálních chemiků a elektrochemiků /11./. Brno (CZ), 01.06.2011-02.06.2011]
Grant CEP: GA AV ČR IAA100100920; GA ČR GD106/09/H035
Výzkumný záměr: CEZ:AV0Z20410507
Klíčová slova: grain boundary * magnetism * segregation * nikel
Kód oboru RIV: BM - Fyzika pevných látek a magnetismus

We present a detailed theoretical study of segregation of sp-elements from the 3rd-5th period (Al, Si, P, S, Ga, Ge, As, Se, In, Sn, Sb and Te) at the Sigma5(210) grain boundary (GB) in fcc FM Ni. Whereas there is a slight enhancement of magnetization at the clean GB and FS with respect to bulk nickel (3–7% and 24%, respectively), the studied impurities entirely kill or strongly reduce ferromagnetism at the GB so that magnetically dead layers are formed. We determine the preferred segregation sites at the GB for the impurities studied, their segregation enthalpies and strengthening/embrittling energies. We find interstitially segregated Si and P and substitutionally segregated Al as a GB cohesion enhancer, and interstitially segregated S, Ge, As, Se and substitutionally segregated Ga, In, Sn, Sb and Te as GB embrittlers in Ni. As there is very little experimental information on GB segregation in nickel most of the present results are theoretical predictions which may motivate future experimental work.
Trvalý link: http://hdl.handle.net/11104/0201323