Cyclic magnetic-field-induced deformation and magneto-mechanical fatigue of Ni-Mn-Ga ferromagnetic martensites

P. Müllner, V. A. Chemenko, D. Mukherji, G. Kostorz

Research output: Contribution to journalConference articlepeer-review

11 Scopus citations

Abstract

Four Ni-Mn-Ga single crystals exhibiting modulated 10M and 14M martensites were exposed to rotating magnetic fields of 1 and 2 T. Large periodic magnetic-field-induced strains were obtained for crystals that had been subjected to a mechanical stress while the martensite formed on cooling and to deformation in a magnetic field prior to the experiments with rotating field. A reduction of the magnetic-field-induced strain and fracture occurred when the field-induced strain was close to the transformation strain whereas a constant magneto-mechanical response was detected over more than 10 million field cycles when the field-induced strain was small. The cyclic magneto-mechanical response is related to the interaction of groups of twinning dislocations and twin boundaries. If the dislocations move in large groups, they nucleate cracks at twin boundaries. If the dislocations move in small groups, no cracks are formed resulting in a long lifetime.

Original languageEnglish
Pages (from-to)415-420
Number of pages6
JournalMaterials Research Society Symposium Proceedings
Volume785
DOIs
StatePublished - 2003
EventMaterials and Devices for Smart Systems - Boston, MA, United States
Duration: 1 Dec 20035 Dec 2003

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