Stability of incommensurately modulated Ni50Mn27Ga22Fe1 10M martensite under uniaxial tensile stress

journal article in Web of Science

English

We investigate the incommensurately modulated crystal structure in the Ni50Mn27Ga22Fe1 magnetic shape memory alloy. We focus on temperature- and stress-induced changes, particularly measuring the a and b lattice parameters and the monoclinic angle. The in-situ XRD experiment shows that the thermally-induced commensurate-incommensurate (C-IC) transition coincides with the change of the average lattice symmetry from monoclinic to orthorhombic. The thermally-induced IC structure is stable under uniaxial tensile stress along the a-axis for deformation epsilon < 0.8 %. A mixture of the IC and C structures appears for epsilon > 0.8 % and the changes become irreversible. The volume fraction of the C structure further increases with increasing deformation. These results provide vital initial insights into the structural evolution of Ni-Mn-Ga alloys and enable us to establish the role of C and IC structures in their extraordinarily high mobility of twin boundaries.

Magnetic shape memory; Ni-Mn-Ga; X-ray diffraction; Incommensurately modulated crystal structure

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

1. 7. 2024

PERGAMON-ELSEVIER SCIENCE LTD

OXFORD

1359-6462

SCRIPTA MATERIALIA

247

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United States of America

116096

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6

https://www.sciencedirect.com/science/article/pii/S1359646224001325