Název: QUANTUM-MECHANICAL STUDY OF INTERNAL STRUCTURAL TRANSFORMATIONS IN Pb-SUPERSATURATED Pb-Sn ALLOYS
Autoři: Friák, Martin ; Čípek, Petr ; Pavlů, J. ; Roupcová, Pavla ; Miháliková, Ivana ; Msallamová, Š. ; Michalcová, A.
Typ dokumentu: Příspěvky z konference
Konference/Akce: NANOCON 2023 - International Conference on Nanomaterials - Research & Application /15./, Brno (CZ), 20231018
Rok: 2024
Jazyk: eng
Edice: NANOCON Conference Proceedings
Abstrakt: Motivated by a decades-long controversy related to the crystal structure of Pb-supersaturated solid solutions of Pb in Sn, we have performed a quantum-mechanical study of these materials. Focusing on both body-centred-tetragonal beta-Sn and simple-hexagonal gamma-Sn structures, we have computed properties of two alloys with the chemical composition Pb5Sn11, i.e. 31.25 at. % Pb, which is close to the composition of the experimentally found alloy (30 at. % Pb). The 16-atom computational supercells were designed as multiples of the elemental beta- and gamma-Sn unit cells, where the Pb atoms were distributed according to the special quasi-random structure (SQS) concept. Full structural relaxations of both beta- and gamma-phase-based alloys resulted in very significant re-arrangements into structures which do not exhibit any apparent structural features typical for the original alloys, and are, therefore, difficult to classify. The formation energies of the beta- and gamma-phase-originating equilibrium phases are 50 meV/atom and 53 meV/atom, respectively. Therefore, they are not stable with respect to the decomposition into the elemental lead and tin. Moreover, our calculations of elastic constants of both phases revealed that they are close to mechanical instability. Our results indicate that the studied Pb-supersaturated Pb-Sn solid solutions may be prone to structural instability, transformations into different phases and decomposition. Our findings may contribute into the identification of the reason why the subsequent experimental studies did not reproduce the initial published data.
Klíčová slova: crystal; Pb-Sn alloys; quantum-mechanical calculations; stability; supersaturation; tin
Číslo projektu: GA22-05801S (CEP)
Poskytovatel projektu: GA ČR
Zdrojový dokument: NANOCON 2023 Conference Proceedings, ISBN 978-80-88365-15-0, ISSN 2694-930X

Instituce: Ústav fyziky materiálů AV ČR (web)
Informace o dostupnosti dokumentu: Dokument je dostupný v příslušném ústavu Akademie věd ČR.
Původní záznam: https://hdl.handle.net/11104/0354923

Trvalý odkaz NUŠL: http://www.nusl.cz/ntk/nusl-622625


Záznam je zařazen do těchto sbírek:
Věda a výzkum > AV ČR > Ústav fyziky materiálů
Konferenční materiály > Příspěvky z konference