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Original title:
QUANTUM-MECHANICAL STUDY OF INTERNAL STRUCTURAL TRANSFORMATIONS IN Pb-SUPERSATURATED Pb-Sn ALLOYS
Authors: Friák, Martin ; Čípek, Petr ; Pavlů, J. ; Roupcová, Pavla ; Miháliková, Ivana ; Msallamová, Š. ; Michalcová, A.
Document type: Papers
Conference/Event: NANOCON 2023 - International Conference on Nanomaterials - Research & Application /15./, Brno (CZ), 20231018
Year: 2024
Language: eng
Series: NANOCON Conference Proceedings
Abstract: 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.
Keywords: crystal; Pb-Sn alloys; quantum-mechanical calculations; stability; supersaturation; tin
Project no.: GA22-05801S (CEP)
Funding provider: GA ČR
Host item entry: NANOCON 2023 Conference Proceedings, ISBN 978-80-88365-15-0, ISSN 2694-930X
Institution: Institute of Physics of Materials AS ČR (web)
Document availability information: Fulltext is available at the institute of the Academy of Sciences.
Original record: https://hdl.handle.net/11104/0354923
Permalink: http://www.nusl.cz/ntk/nusl-622625
The record appears in these collections:
Research > Institutes ASCR > Institute of Physics of Materials
Conference materials > Papers
Authors: Friák, Martin ; Čípek, Petr ; Pavlů, J. ; Roupcová, Pavla ; Miháliková, Ivana ; Msallamová, Š. ; Michalcová, A.
Document type: Papers
Conference/Event: NANOCON 2023 - International Conference on Nanomaterials - Research & Application /15./, Brno (CZ), 20231018
Year: 2024
Language: eng
Series: NANOCON Conference Proceedings
Abstract: 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.
Keywords: crystal; Pb-Sn alloys; quantum-mechanical calculations; stability; supersaturation; tin
Project no.: GA22-05801S (CEP)
Funding provider: GA ČR
Host item entry: NANOCON 2023 Conference Proceedings, ISBN 978-80-88365-15-0, ISSN 2694-930X
Institution: Institute of Physics of Materials AS ČR (web)
Document availability information: Fulltext is available at the institute of the Academy of Sciences.
Original record: https://hdl.handle.net/11104/0354923
Permalink: http://www.nusl.cz/ntk/nusl-622625
The record appears in these collections:
Research > Institutes ASCR > Institute of Physics of Materials
Conference materials > Papers
Record created 2024-07-27, last modified 2024-07-27