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@article{1616016,
author = {Miháliková, Ivana and Friák, Martin and Koutná, Nikola and Holec, David and Šob, Mojmír},
article_location = {Basel},
article_number = {9},
doi = {http://dx.doi.org/10.3390/ma12091430},
keywords = {Fe3Al; Fe-Al; vacancies; magnetism; ab initio; disorder; superalloys},
language = {eng},
issn = {1996-1944},
journal = {Materials},
title = {An Ab Initio Study of Vacancies in Disordered Magnetic Systems: A Case Study of Fe-Rich Fe-Al Phases},
url = {https://www.mdpi.com/1996-1944/12/9/1430},
volume = {12},
year = {2019}
}
TY - JOUR
ID - 1616016
AU - Miháliková, Ivana - Friák, Martin - Koutná, Nikola - Holec, David - Šob, Mojmír
PY - 2019
TI - An Ab Initio Study of Vacancies in Disordered Magnetic Systems: A Case Study of Fe-Rich Fe-Al Phases
JF - Materials
VL - 12
IS - 9
SP - 1-16
EP - 1-16
PB - MDPI AG
SN - 19961944
KW - Fe3Al
KW - Fe-Al
KW - vacancies
KW - magnetism
KW - ab initio
KW - disorder
KW - superalloys
UR - https://www.mdpi.com/1996-1944/12/9/1430
L2 - https://www.mdpi.com/1996-1944/12/9/1430
N2 - We have performed quantum-mechanical calculations to examine the impact of disorder on thermodynamic, structural and electronic (magnetic) properties of Fe-Al systems with vacancies. A series of supercells was used and their properties were computed employing density-functional theory (DFT) as implemented in the VASP package. Our case study is primarily aimed at a disordered solid solution Fe81.25Al18.75 but we have compared our results also with those obtained for the ordered Fe3Al intermetallic compound for which experimental data exist in literature. Both phases are found in Fe-Al-based superalloys. The Fe-18.75at.%Al solid solution was simulated using special quasirandom structures (SQS) in three different disordered states with a different distribution of Al atoms. In particular, we have considered a general disordered case (an A2-like variant), the case without the first nearest neighbor Al-Al pairs (a B2-like distribution of atoms) and also the case without both the first and second nearest neighbor Al-Al pairs (the D03-like variant, in fact, an Fe-rich Fe3Al phase). The vacancy formation energies as well as the volumes of (fully relaxed) supercells with vacancies showed a large scatter for the disordered systems. The vacancy formation energies decrease with increasing concentration of Al atoms in the first coordination shell around the vacancy (an anti-correlation) for all disordered cases studied. The computed volumes of vacancies were found significantly lower (by 25-60%) when compared with the equilibrium volume of the missing atoms in their elemental states. Lastly, we have analyzed interactions between the vacancies and the Fe atoms and evaluated vacancy-induced changes in local magnetic moments of Fe atoms.
ER -
MIHÁLIKOVÁ, Ivana, Martin FRIÁK, Nikola KOUTNÁ, David HOLEC a Mojmír ŠOB. An Ab Initio Study of Vacancies in Disordered Magnetic Systems: A Case Study of Fe-Rich Fe-Al Phases. \textit{Materials}. Basel: MDPI AG, 2019, roč.~12, č.~9, s.~1-16. ISSN~1996-1944. Dostupné z: https://dx.doi.org/10.3390/ma12091430.
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