Shape Memory Effect and Magnetostriction in Rapidly Solidified Fe-29.6 at%Pd Alloy

Abstract

Rapidly solidified ferromagnetic shape memory Fe-29.6 at% Pd alloy was fabricated to develop a new type of actuator material responded to magnetic field. The thin ribbon samples which were made by the originally designed electro magnetically controlled nozzleless melt-spinning method showed stronger crystal anisotropy and larger shape memory effect. Magnetostriction increased with increasing magnetic field and its value changed with increasing temperature up to about 1800 microstrain at an applied magnetic field, H=8.0×105 A/m (=10 kOe), at just below the inverse phase transformation temperature (As). This phenomenon may be caused by the re-arrangements of the activated martensitic twin variants due to applying magnetic field. The dependencies of shape memory effect and giant magnetostriction on metallurgical microstructures are discussed from the viewpoint of the crystal anisotropy and the grain boundary character distribution.