ACTA

Martensitic Transformation in Co-Based Ferromagnetic Shape Memory Alloy

J. Kopeček^a, F. Yokaichiya^{b, c}, F. Laufek^d, M. Jarošová^e, K. Jurek^e, J. Drahokoupil^a, S. Sedláková-Ignácová^a, P. Molnár^a and O. Heczko^a
^aInstitute of Physics of the AS CR, Na Slovance 2, 182 21 Praha, Czech Republic
^bLaboratório Nacional de Luz Síncrotron, Campinas, Brazil
^cHelmholtz-Zentrum Berlin, Hahn-Meitner-Platz 1, 14109 Berlin, Germany
^dCzech Geological Survey, Geologická 6, 152 00 Praha 5, Czech Republic
^eInstitute of Physics of the AS CR, Cukrovarnická 10/112, 162 00 Praha, Czech Republic

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The Co₃₈Ni₃₃Al₂₉ alloy in both powder and bulk state was investigated in the presented study using neutron diffraction on E9 high resolution powder diffractometer at HZB (BER II). The reverse martensitic phase transformation from the tetragonal martensitic phase into the cubic austenitic phase was observed with the phase coexistence within the temperatures from 183 K to 133 K. The fcc cobalt solid solution particles distributed in the transforming matrix remained in the same state through the whole temperature range. The obtained results agree with magnetization measurements on the same annealed sample. The powder data are compared with experiments on bulk sample, although there was a texture present. The obtained results provide further information about the phase transition process in this important class of ferromagnetic shape memory alloys.

DOI: 10.12693/APhysPolA.122.475
PACS numbers: 78.40.Kc, 61.05.fm, 81.30.Kf, 81.40.Ef