Interfacial Stresses and Anomalous Shape of Pseudoelastic Deformation Curves in Ni49Fe18Ga27Co6 Alloy Crystals Compressed along the [011]A Axis
- Авторы: Malygin G.1, Nikolaev V.1, Krymov V.1, Pul’nev S.1, Stepanov S.1
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Учреждения:
- Ioffe Institute
- Выпуск: Том 64, № 6 (2019)
- Страницы: 819-827
- Раздел: Solid State
- URL: https://journals.rcsi.science/1063-7842/article/view/203553
- DOI: https://doi.org/10.1134/S1063784219060124
- ID: 203553
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Аннотация
We have performed experimental and theoretical investigation of the anomalous form of the compression diagrams and shape memory restoration curves in Ni49Fe18Ga27Co6 alloy crystals deformed by uniaxial compression along the [011]A crystallographic direction (A-austenite) in the temperature range of 200–350 K. It is found that in the investigated temperature range, all compression diagrams contain anomalous segments of smooth and sharp decrease in deforming stresses. It is shown that the segments of a smooth decrease in stress are associated with peculiarities in martensite reaction L12 → 14M, while segments of a sharp drop are due to instability of martensite reactions 14M → L10 and L12 → L10. A possible source of reaction instability is associated with interfacial stresses at the interfaces between the martensite and austenite phases (lamellas) due to different elastic moduli of contacting phases. The magnitude of these stresses is significant in the case of 14M → L10 and L12 → L10 transformations, which induces a sharp drop of the deforming stress, while the restoration of the shape memory effect is of a burst nature. It is established that the contribution of interfacial stresses to the free energy of martensite transformation is smaller than the dissipative (entropy) contribution to this energy; however, interfacial stresses higher than a certain threshold strongly affect transformation kinetics and, hence, determine the strongly anomalous shape of pseudoelastic deformation curves and burst restoration of the shape memory effect.
Об авторах
G. Malygin
Ioffe Institute
Автор, ответственный за переписку.
Email: malygin.ga@mail.ioffe.ru
Россия, St. Petersburg, 194021
V. Nikolaev
Ioffe Institute
Email: malygin.ga@mail.ioffe.ru
Россия, St. Petersburg, 194021
V. Krymov
Ioffe Institute
Email: malygin.ga@mail.ioffe.ru
Россия, St. Petersburg, 194021
S. Pul’nev
Ioffe Institute
Email: malygin.ga@mail.ioffe.ru
Россия, St. Petersburg, 194021
S. Stepanov
Ioffe Institute
Email: malygin.ga@mail.ioffe.ru
Россия, St. Petersburg, 194021