Magnetically driven shape memory alloys

Enkovaara, Jussi; Ayuela, Andrés; Zayak, Alexey T.; Entel, P.; Nordström, Lars; Dubé, Marc A.; Jalkanen, Jari; Impola, J.; Nieminen, Risto M.

doi:10.1016/j.msea.2003.10.330

Cited by 95 publications

(52 citation statements)

References 45 publications

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“…[1][2][3] The shape memory effect can not only be controlled by changing the temperature, as it occurs in traditional shape memory alloys, but also by varying the magnetic field up to moderate field values. The latter makes them of noteworthy interest for developing new thermal or magnetically driven actuators.…”

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confidence: 99%

Microstructure and magnetic properties of Ni50Mn37Sn13 Heusler alloy ribbons

Santos

Sánchez

Álvarez

et al. 2008

Journal of Applied Physics

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The Heusler alloy Ni 50 Mn 37 Sn 13 was successfully produced as ribbon flakes of thickness around 7-10 m melt spinning. Fracture cross section micrographs in the ribbon show the formation of a microcrystalline columnarlike microstructure, with their longer axes perpendicular to the ribbon plane. Phase transition temperatures of the martensite-austenite transformation were found to be M S = 218 K, M f = 207 K, A S = 224 K, and A f = 232 K; the thermal hysteresis of the transformation is 15 K. Ferromagnetic L2 1 bcc austenite phase shows a Curie point of 313 K, with cell parameter a = 0.5971͑5͒ nm at 298 K, transforming into a modulated 7M orthorhombic martensite with a = 0.6121͑7͒ nm, b = 0.6058͑8͒ nm, and c = 0.5660͑2͒ nm, at 150 K. © 2008 American Institute of Physics. ͓DOI: 10.1063/1.2832330͔Ferromagnetic shape memory alloys ͑FSMA͒ are of considerable interest because of their exceptional magnetoelastic properties.1-3 The shape memory effect can not only be controlled by changing the temperature, as it occurs in traditional shape memory alloys, but also by varying the magnetic field up to moderate field values. The latter makes them of noteworthy interest for developing new thermal or magnetically driven actuators. 4Among the Heusler alloys that exhibit magnetic shape memory effect, the most extensively studied are those of the Ni-Mn-Ga system. However, to overcome some of the problems related to practical application, such as the high cost of gallium and the low martensitic transformation temperature that they usually present, the search for Ga-free alloys has been recently attempted. Martensitic transformation in ferromagnetic Heusler Ni 50 Mn 50−x Sn x alloys with 10ഛ x ഛ 16.5 was first reported by Sutou et al. 5 Later, Krenke et al. studied phase transformations and magnetic and magnetocaloric properties of the Ni 50 Mn 50−x Sn x alloy series with 5 ഛ x ഛ 25. 6,7 Samples with x = 0.13 and 0.15 are ferromagnetic in the martensitic state undergoing a first order martensitic-austenitic structural transition at a temperature below the respective Curie points of both phases. At room temperature, the alloy with x = 0.13 is martensitic, and the martensite-austenite transformation occurs around room temperature. Brown et al. 8 12 They report magnetic entropy changes up to 10.4 J / kg K at 10 kOe for x = 7. Ni-Mn-Sn system is, therefore, of prospective importance as FSMA and as promising magnetic refrigerant alloy. In all these cases, alloys were produced as bulk polycrystalline samples.In this work we produced, as far as we know for the first time, Ni-Mn-Sn alloys by rapid solidification. This procedure offers several potential advantages for the fabrication of the shape memory materials such as avoiding the homogenization annealing step to reach a single phase alloy and the synthesis of highly textured polycrystalline samples. Moreover, ribbon shape is appropriate for direct use in practical devices. In view of its interesting properties, 6,7 we have selected the alloy Ni 50 Mn 37 Sn 13 and studied its microstr...

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confidence: 99%

Microstructure and magnetic properties of Ni50Mn37Sn13 Heusler alloy ribbons

Santos

Sánchez

Álvarez

et al. 2008

Journal of Applied Physics

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“…28.12). Magnetic actuation can be implemented by using electromagnetic interactions [61], permanent magnets [62], magnetostrictive materials, or shape memory alloys [63,64]. These actuators present important advantages with respect to other types of actuation; for example, they allow wireless operation and operate at low or zero voltage, potentially enabling their use in remote and hostile environments.…”

Section: Magnetic Mems and Electrodeposition Of Magnetic Materialsmentioning

confidence: 99%

Microelectromechanical Systems

Zangari

2010

Modern Electroplating

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“…It was noticed that off-stoichiometric alloys often demonstrate higher shape memory effect than stoichiometric Ni 2 MnGa alloys [25][26][27][28][29][30].…”

Section: Introductionmentioning

confidence: 99%

Multiscale twin hierarchy in NiMnGa shape memory alloys with Fe and Cu

Barabash

Popov

et al. 2015

Acta Materialia

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X-ray microdiffraction and scanning electron microscopy studies reveal 10 M martensitic structure with a highly correlated multiscale twin hierarchy organization in NiMnGaFeCu shape memory alloys. High compatibility is found at the twin interfaces resulting in a highly correlated twinned lattice orientation across several laminate levels. The lattice unit cell is described as monoclinic I-centered with a = 4.28 Å , b = 4.27 Å , c = 5.40 Å , c = 78.5°. The modulation is found parallel to the b axis. Thin tapered needle-like lamellae and branching are observed near the twin boundaries.

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Magnetically driven shape memory alloys

Cited by 95 publications

References 45 publications

Microstructure and magnetic properties of Ni50Mn37Sn13 Heusler alloy ribbons

Microstructure and magnetic properties of Ni50Mn37Sn13 Heusler alloy ribbons

Microelectromechanical Systems

Multiscale twin hierarchy in NiMnGa shape memory alloys with Fe and Cu

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