Magnetomechanical performance of directionally solidified Fe–Ga alloys

Abstract

Iron-gallium alloys can produce magnetostrictions of ∼400ppm and might serve as mechanically robust actuator/sensing materials. However, for polycrystalline Fe–Ga alloys, the magnetostrictive performance decreases with the increasing deviations from the ideal ⟨100⟩ texture. In this paper, three directionally solidified Fe–Ga alloys with gallium contents of 17, 18.4, and 19.5at.% were characterized at ambient temperature. These specimens exhibit high d33 and magnetic permeability when subjected to applied magnetic fields, indicating their suitability for light weight actuator applications but not for high force applications due to their low saturation magnetostriction and hence low blocking force. All the alloys produce significant changes in magnetization, around 0.7Ms–0.8Ms when subjected to cyclic compressive stresses of 51MPa, making them promising candidate materials for sensing and energy harvesting applications. However, eddy current effects may easily become a problem when such materials are subjected to a high frequency vibration or magnetic field due to their intrinsic high magnetic permeability.