Abstract
Some NiMnGa 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 alloy at high temperatures up to 1000 °C which show that the magnetic shape memory alloy (MSMA) 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.

 

Some NiMnGa 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 alloy at high temperatures up to 1000 °C which show that the magnetic shape memory alloy (MSMA) 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.