Transformation Paths from Cubic to Low-Symmetry Structures in Heusler Ni2MnGa Compound

Abstract In order to explain the formation of low-temperature phases in stoichiometric Ni2MnGa magnetic shape memory alloy, we investigate the phase transformation paths from cubic austenite with Heusler structure to low-symmetry martensitic structures. We used ab initio calculations combined with t...

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Autores principales:	Martin Zelený, Ladislav Straka, Alexei Sozinov, Oleg Heczko
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2018
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/8acb733344c94f5fbbb5f3595c507247
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spelling	oai:doaj.org-article:8acb733344c94f5fbbb5f3595c5072472021-12-02T12:31:56ZTransformation Paths from Cubic to Low-Symmetry Structures in Heusler Ni2MnGa Compound10.1038/s41598-018-25598-z2045-2322https://doaj.org/article/8acb733344c94f5fbbb5f3595c5072472018-05-01T00:00:00Zhttps://doi.org/10.1038/s41598-018-25598-zhttps://doaj.org/toc/2045-2322Abstract In order to explain the formation of low-temperature phases in stoichiometric Ni2MnGa magnetic shape memory alloy, we investigate the phase transformation paths from cubic austenite with Heusler structure to low-symmetry martensitic structures. We used ab initio calculations combined with the generalized solid state nudged elastic band method to determine the minimum energy path and corresponding changes in crystal lattice. The four-, five-, and seven-layered modulated phases of martensite (4O, 10M, and 14M) are built as the relaxed nanotwinned non-modulated (NM) phase. Despite having a total energy larger than the other martensitic phases, the 10M phase will spontaneously form at 0 K, because there is no energy barrier on the path and the energy decreases with a large negative slope. Moreover, a similar negative slope in the beginning of path is found also for the transformation to the 6M premartensite, which appears as a local minimum on the path leading further to 10M martensite. Transformation paths to other structures exhibit more or less significant barriers in the beginning hindering such a transformation from austenite. These findings correspond to experiment and demonstrates that the kinetics of the transformation is decisive for the selection of the particular low-symmetry structure.Martin ZelenýLadislav StrakaAlexei SozinovOleg HeczkoNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 8, Iss 1, Pp 1-8 (2018)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q Martin Zelený Ladislav Straka Alexei Sozinov Oleg Heczko Transformation Paths from Cubic to Low-Symmetry Structures in Heusler Ni2MnGa Compound
description	Abstract In order to explain the formation of low-temperature phases in stoichiometric Ni2MnGa magnetic shape memory alloy, we investigate the phase transformation paths from cubic austenite with Heusler structure to low-symmetry martensitic structures. We used ab initio calculations combined with the generalized solid state nudged elastic band method to determine the minimum energy path and corresponding changes in crystal lattice. The four-, five-, and seven-layered modulated phases of martensite (4O, 10M, and 14M) are built as the relaxed nanotwinned non-modulated (NM) phase. Despite having a total energy larger than the other martensitic phases, the 10M phase will spontaneously form at 0 K, because there is no energy barrier on the path and the energy decreases with a large negative slope. Moreover, a similar negative slope in the beginning of path is found also for the transformation to the 6M premartensite, which appears as a local minimum on the path leading further to 10M martensite. Transformation paths to other structures exhibit more or less significant barriers in the beginning hindering such a transformation from austenite. These findings correspond to experiment and demonstrates that the kinetics of the transformation is decisive for the selection of the particular low-symmetry structure.
format	article
author	Martin Zelený Ladislav Straka Alexei Sozinov Oleg Heczko
author_facet	Martin Zelený Ladislav Straka Alexei Sozinov Oleg Heczko
author_sort	Martin Zelený
title	Transformation Paths from Cubic to Low-Symmetry Structures in Heusler Ni2MnGa Compound
title_short	Transformation Paths from Cubic to Low-Symmetry Structures in Heusler Ni2MnGa Compound
title_full	Transformation Paths from Cubic to Low-Symmetry Structures in Heusler Ni2MnGa Compound
title_fullStr	Transformation Paths from Cubic to Low-Symmetry Structures in Heusler Ni2MnGa Compound
title_full_unstemmed	Transformation Paths from Cubic to Low-Symmetry Structures in Heusler Ni2MnGa Compound
title_sort	transformation paths from cubic to low-symmetry structures in heusler ni2mnga compound
publisher	Nature Portfolio
publishDate	2018
url	https://doaj.org/article/8acb733344c94f5fbbb5f3595c507247
work_keys_str_mv	AT martinzeleny transformationpathsfromcubictolowsymmetrystructuresinheuslerni2mngacompound AT ladislavstraka transformationpathsfromcubictolowsymmetrystructuresinheuslerni2mngacompound AT alexeisozinov transformationpathsfromcubictolowsymmetrystructuresinheuslerni2mngacompound AT olegheczko transformationpathsfromcubictolowsymmetrystructuresinheuslerni2mngacompound
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Transformation Paths from Cubic to Low-Symmetry Structures in Heusler Ni2MnGa Compound

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