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Analysis of structural and functional properties of Ni50Mn30Ga20 after plastic deformation

: Böhm, A.; Roth, S.; Naumann, G.; Drossel, W.-G.; Neugebauer, Reimund


Materials Science and Engineering, A. Structural materials, properties, microstructure and processing 481-482 (2008), pp.266-270
ISSN: 0921-5093
ISSN: 1873-4936
European Symposium on Martensitic Transformations (ESOMAT) <7, 2006, Bochum>
Journal Article, Conference Paper
Fraunhofer IWU ()
magnetic shape memory alloy; Ni-Mn-Ga; martensitic transformation; compression test; hot-rolling

Some Ni-Mn-Ga single crystals exhibit a magnetic-field-induced strain (MFIS) in the low-temperature martensitic phase. In order to obtain such MFIS in polycrystalline samples, the use of textured samples is most promising. The paper describes experimental results of compression tests of a Ni50Mn30Ga20 (at.%) alloy at high temperatures up to 1000 ?C which show that the magnetic shape memory alloy exhibits a good plastic deformation behavior above the ordering temperature in the B2 (CsCl) structure. Flow curves were obtained for various strain rates. Experiments using the hot-rolling process were successful. The results show that it is possible to obtain pre-orientation of the twinned martensitic structure. The cast and hot-rolled specimens were characterized by differential scanning calorimetry, X-ray diffraction and optical microscopy using differential interference contrast. The changes in structural properties of specimens after plastic deformation are presented and discussed.