Publication detail

Constant plane shift model: Structure analysis of martensitic phases in Ni50Mn27Ga22Fe1 beyond non-modulated building blocks

VINOGRADOVA, M. SOZINOV, A. STRAKA, L. VEŘTÁT, P. HECZKO, O. ZELENÝ, M. CHULIST, R. LÄHDERANTA, E. ULLAKKO, K.

English title

Constant plane shift model: Structure analysis of martensitic phases in Ni50Mn27Ga22Fe1 beyond non-modulated building blocks

Type

journal article in Web of Science

Language

en

Original abstract

Martensites of Ni-Mn-Ga-based alloys consist of hierarchical twinning domains spanning from micro-to nanoscale. This affects the diffraction pattern and thus can decrease the accuracy of the determination of the crystal structure. We propose a method to obtain different martensitic phases in Ni-Mn-Ga-Fe alloy with simplified variant microstructures and domain sizes of more than 2 micrometers. The use of simplified variant microstructures allows the influence of nanometer-scale domains on diffraction line position to be circumvented and enabls the comparison of the lattice parameters of non-modulated (NM), five-layered modulated (10M), and seven-layered (14M) phases in the same temperature range due to the large hysteresis of the intermartensitic transformations. It is found that the short crystallo-graphic axes in NM, 14M, and 10M martensites at the same temperature have different lengths. As a result, equilibrium NM structure building blocks cannot be used to build the crystal structures of 14M and 10M martensites. Instead, we introduce a constant plane shift model with identical shift values of the nearest planes (110) along [(1) over bar 10] or [1 (1) over bar0] as a replacement for the tetragonal building blocks model. The work demonstrates that plane shift values differ dramatically between mar-tensites, which agrees with ab initio calculations. The application of the constant plane shift and hard sphere models in modulated lattices for atomic-level twinning considerations is discussed.

English abstract

Martensites of Ni-Mn-Ga-based alloys consist of hierarchical twinning domains spanning from micro-to nanoscale. This affects the diffraction pattern and thus can decrease the accuracy of the determination of the crystal structure. We propose a method to obtain different martensitic phases in Ni-Mn-Ga-Fe alloy with simplified variant microstructures and domain sizes of more than 2 micrometers. The use of simplified variant microstructures allows the influence of nanometer-scale domains on diffraction line position to be circumvented and enabls the comparison of the lattice parameters of non-modulated (NM), five-layered modulated (10M), and seven-layered (14M) phases in the same temperature range due to the large hysteresis of the intermartensitic transformations. It is found that the short crystallo-graphic axes in NM, 14M, and 10M martensites at the same temperature have different lengths. As a result, equilibrium NM structure building blocks cannot be used to build the crystal structures of 14M and 10M martensites. Instead, we introduce a constant plane shift model with identical shift values of the nearest planes (110) along [(1) over bar 10] or [1 (1) over bar0] as a replacement for the tetragonal building blocks model. The work demonstrates that plane shift values differ dramatically between mar-tensites, which agrees with ab initio calculations. The application of the constant plane shift and hard sphere models in modulated lattices for atomic-level twinning considerations is discussed.

Keywords in English

martensite; crystal-structure; temperature-dependence; symmetry; transformation

Released

30.05.2023

Publisher

Elsevier

Location

OXFORD

ISSN

1873-2453

Volume

255

Number

1

Pages from–to

1–11

Pages count

11

BIBTEX


@article{BUT184356,
  author="Mariia {Vinogradova} and Alexei {Sozinov} and Ladislav {Straka} and Petr {Veřtát} and Oleg {Heczko} and Martin {Zelený} and Robert {Chulist} and Erkki {Lähderanta} and Kari {Ullakko},
  title="Constant plane shift model: Structure analysis of martensitic phases in Ni50Mn27Ga22Fe1 beyond non-modulated building blocks",
  year="2023",
  volume="255",
  number="1",
  month="May",
  pages="1--11",
  publisher="Elsevier",
  address="OXFORD",
  issn="1873-2453"
}