Stability and Strength of Transition-Metal Tetraborides and Triborides
The result's identifiers
Result code in IS VaVaI
<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F61989100%3A27740%2F12%3A86085210" target="_blank" >RIV/61989100:27740/12:86085210 - isvavai.cz</a>
Result on the web
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DOI - Digital Object Identifier
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Alternative languages
Result language
angličtina
Original language name
Stability and Strength of Transition-Metal Tetraborides and Triborides
Original language description
Using density functional theory, we show that the long-believed transition-metal tetraborides (TB4) of tungsten and molybdenum are in fact triborides (TB3). This finding is supported by thermodynamic, mechanical, and phonon instabilities of TB4, and it challenges the previously proposed origin of superhardness of these compounds and the predictability of the generally used hardness model. Theoretical calculations for the newly identified stable TB3 structure correctly reproduce their structural and mechanical properties, as well as the experimental x-ray diffraction pattern. However, the relatively low shear moduli and strengths suggest that TB3 cannot be intrinsically stronger than c-BN. The origin of the lattice instability of TB3 under large shear strain that occurs at the atomic level during plastic deformation can be attributed to valence charge depletion between boron and metal atoms, which enables easy sliding of boron layers between the metal ones.
Czech name
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Czech description
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Classification
Type
J<sub>x</sub> - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)
CEP classification
BM - Solid-state physics and magnetism
OECD FORD branch
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Result continuities
Project
<a href="/en/project/ED1.1.00%2F02.0070" target="_blank" >ED1.1.00/02.0070: IT4Innovations Centre of Excellence</a><br>
Continuities
P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)
Others
Publication year
2012
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 Letters
ISSN
0031-9007
e-ISSN
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Volume of the periodical
108
Issue of the periodical within the volume
22 June 2012
Country of publishing house
US - UNITED STATES
Number of pages
5
Pages from-to
255502-255506
UT code for WoS article
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EID of the result in the Scopus database
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