Ab initio study of chemical disorder as an effective stabilizing mechanism of bcc-based TiAl(+Mo)
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68081723%3A_____%2F20%3A00532800" target="_blank" >RIV/68081723:_____/20:00532800 - isvavai.cz</a>
Result on the web
<a href="https://journals.aps.org/prmaterials/abstract/10.1103/PhysRevMaterials.4.103604" target="_blank" >https://journals.aps.org/prmaterials/abstract/10.1103/PhysRevMaterials.4.103604</a>
DOI - Digital Object Identifier
<a href="http://dx.doi.org/10.1103/PhysRevMaterials.4.103604" target="_blank" >10.1103/PhysRevMaterials.4.103604</a>
Alternative languages
Result language
angličtina
Original language name
Ab initio study of chemical disorder as an effective stabilizing mechanism of bcc-based TiAl(+Mo)
Original language description
To shed a new light on the complex microstructural evolution in the Ti–Al–Mo system, we employnab initio calculations to study bcc-fcc structural transformations of ordered βo-TiAl(+Mo) and disorderednβ-TiAl(+Mo) to ordered γ -TiAl(+Mo) and hypothetically assumed disordered γdis-TiAl(+Mo) alloys, respectively.nIn particular, tetragonal (Bain’s path) and trigonal transformations are combined with the concept ofnspecial quasirandom structures (SQS) and examined. Our calculations of the ordered phases show that the βo →nγ tetragonal transformation of TiAl is barrierless, i.e., proceeds spontaneously, reflecting the genuine structuralninstability of the βo phase. Upon alloying of ≈7.4 at.%Mo, a small barrier between βo and γ -related local energynminima is formed. Yet a higher Mo content of ≈9 at.% leads to an opposite-direction barrierless transformationnγ → βo, i.e., fully stabilizing the βo phase. Considering the disordered phases, the β-Ti0.5Al0.5−xMox andnγdis-Ti0.5Al0.5−xMox are energetically very close. Importantly, for all here-considered compositions up to 11 at.%nof Mo, a small energy barrier separates β-TiAl(+Mo) and γdis-TiAl(+Mo) energy minima. Finally, a trigonalnpath was studied as an alternative transformation connecting disordered β and γdis-TiAl phases, but it turns outnthat it exhibits an energy barrier over 60meV/at. which, in comparison to the Bain’s path with 9meV/at. barrier,neffectively disqualifies the trigonal transformation for the TiAl system.
Czech name
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Czech description
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Classification
Type
J<sub>imp</sub> - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10302 - Condensed matter physics (including formerly solid state physics, supercond.)
Result continuities
Project
<a href="/en/project/LQ1601" target="_blank" >LQ1601: CEITEC 2020</a><br>
Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2020
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
Physical Review Materials
ISSN
2475-9953
e-ISSN
—
Volume of the periodical
4
Issue of the periodical within the volume
10
Country of publishing house
US - UNITED STATES
Number of pages
14
Pages from-to
103604
UT code for WoS article
000576705800004
EID of the result in the Scopus database
2-s2.0-85094142110