Effect of severe plastic deformation by torsion on the properties and structure of the Ni54Mn21Ga25 and Ni54Mn20Fe1Ga25 alloys

Abstract

The effect of one-percent substitution of iron for manganese on the physical (magnetic, electrical, thermal, and galvanomagnetic) properties and the crystal structure of the Ni 54 Mn 21 Ga 25 alloy has been investigated. It has been demonstrated that the deviation of the alloy composition from the stoichiometric composition Ni 50 Mn 25 Ga 25 leads to the formation of a mixed ferromagnetic-antiferromagnetic state. The atomic disordering and nanostructuring of the alloys under investigation due to the severe plastic deformation by torsion in Bridgman anvils to sizes of 10–20 nm result in the suppression of reversible magnetically controlled shape memory effects.