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We have studied the effect of tensile axis on strain induced martensitic formation in SUS304 steel. Single crystal

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Ferromagnetic shape memory alloy Ni-25 at%Mn-23 at%Ga prepared by melting in an electric furnace was investigated to study compression properties at various temperatures with and without magnetic field. The magnetic field is applied parallel to the compression axis at a temperature below martensite finish temperature and at a temperature above austenite finish temperature. Triggering stress necessary for rearrangement of martensite variants is reduced by 0:76$1:68 MPa (i.e., 2:5$5:5%) when a magnetic field of 0:4$0:6 T is applied to martensite state. The stress reduction is larger at a higher magnetic field. On the other hand, triggering stress for stress-induced martensite transformation is essentially unchanged under the same magnetic field applied to austenite state. This is due in part to very small changes in Gibbs free energy under magnetic field because of large temperature differences between M s and T c . and because of essentially no difference in magnetization between martensite and austenite phases.

Several ternary Fe-Pt-Pd alloys with the compositions of Fe-(25-x) at% Pt-x at% Pd and Fe-y at% Pt-(30-y) at% Pd were investigated to study their phase transformations in order to develop ductile ferromagnetic shape memory alloys appearing around room temperature. Alloys were prepared by vacuum floating induction melting, followed by hot rolling at 1000 o C and homogenization at 900 o C. Homogenized alloys were heat treated at 650 o C for various periods of time in vacuum for atomic ordering in encapsulated quartz tubes, and quenched into iced water. It was found that in general the transformation temperatures changes with heat treatment time.In the case of Fe-23at.%Pt-2at.%Pd, M s temperature increased and the difference between M s and M f increased with increasing heat treatment time, which was different from Fe 3 Pt where a degree of order becomes one. As heat treatment time increased, there was a tendency in that a strong first-order transformation in the disordered state was replaced by a weak first-order transformation. The Curie temperature of the alloys rose drastically with the addition of Pd, along with the transformation temperatures. Fe-23at.%Pt-2at.%Pd showed good shape memory effect after 8 hours of heat treatment at 650 o C. This alloy showed much better shape recovery than any other binary Fe-Pt and Fe-Pd shape memory alloys.