Stress Induced Phase Transition of Iron-Rhodium Alloys

Stress-induced phase transitions(B2-L1 0 , B2-fcc) on an FeRh alloy were investigated with X-ray diffraction (XRD) and transmission electron microscopy(TEM). An Fe-50.5at%Rh alloy was rolled to 80 μm thickness, and annealed at 1370K for 173ks. Annealed sample sheets were cold rolled at various rolling rates, and changes of the sample alloy on the phase state were investigated with XRD. The L1 0 phase appeared in the early stage of cold work. With heavy work appearance of the fcc phase and consequent decrease of L1 0 were observed. Destruction of the order of B2 phase was also observed with progress of cold working. The crystallography and morphology of stress induced phases were studied with TEM. L1 0 phase grains were appeared as layers of about 100 to 1000nm thickness, and density of dislocations in them were extremely high. The separate appearance of fcc phase from L1 0 phase was found in B2 phase grains. The result is negative to an idea that the Ll 0 phase is an intermediate phase of the B2-fcc transition.