0525125 - FZÚ 2021 RIV CH eng J - Journal Article
Zelený, M. - Heczko, M. - Janovec, J. - Holec, D. - Straka, Ladislav - Heczko, Oleg
The effect of local arrangement of excess Mn on phase stability in Ni-Mn-Ga martensite: an ab initio study.
Shape Memory and Superelasticity. Roč. 6, č. 1 (2020), s. 35-44. ISSN 2199-384X. E-ISSN 2199-3858
R&D Projects: GA ČR(CZ) GA17-00062S
Institutional support: RVO:68378271
Keywords : Ni-Mn-Ga * magnetic shape memory * martensitic transformation * elastic properties * ab initio calculation
OECD category: Condensed matter physics (including formerly solid state physics, supercond.)
Method of publishing: Limited access
https://doi.org/10.1007/s40830-019-00247-0

The effect of excess Mn on the stability of modulation and elastic properties was investigated using ab initio electronic structure calculations in Ni–Mn–Ga magnetic shape memory alloy. We used the structure of four layered modulated martensite known as 4O to describe modulation of the martensitic lattice. We found that elastic properties of stoichiometric 4O martensite are very similar to elastic properties of 10M martensite reported in previous calculations. The modulated structure becomes less stable than nonmodulated martensite above 3 at.% of excess Mn which corresponds very well to experimental observation at low temperature. Elastic properties of NM martensite are not significantly affected by Mn content nor local arrangements of Mn-excess atoms. We also found that Mn-excess atoms prefer occupation of distant positions for low Mn-excess composition. The occupation of closest position is preferred for alloys with higher content of Mn.
Permanent Link: http://hdl.handle.net/11104/0309333