Positron Annihilation Study on Defects and Phase Transition of FeRh Alloys Subjected to High-Speed Deformation

The relations between vacancy-type defects in Fe-40, 45, and 50 at%Rh alloys and stress-induced phase transitions from a B2 phase have been examined by XRD, TEM, and positron annihilation experiments. The specimens were deformed at room temperature by a high-speed compression machine, and the natures of related vacancies and vacancy clusters were examined. The results reveal that structural Rh vacancies exist in non-stoichiometric FeRh alloys, and that lifetimes of the long-lifetime components of the introduced defects change in various manners, depending upon the deformation conditions.