Effect of combined magnetic bias and drive fields on dynamic magnetomechanical properties of Terfenol-D/epoxy 1-3 composites

The dynamic magnetomechanical properties of Terfenol-D/epoxy 1-3 magnetostrictive composites with approximately 50% Terfenol-D volume fraction have been investigated under different combined magnetic bias (HBias=5-140 kA/m) and drive (H3=1-9 kA/m) fields. These properties include elastic moduli (E3H and E3B), dynamic relative permeability (μr33T), dynamic strain coefficient (d33), magnetomechanical coupling coefficient (k33), and the ratio of the dynamic strain coefficient to the dynamic susceptibility (d33/χ33). The changes in the composite properties with applied fields can be explained in terms of domain wall motion followed by saturation. At a low H3 of 1 kA/m, the available non-180 deg. domain state created by residual compressive stresses in the composites results in negative-ΔE, d33, k33, and d33/χ33 maximizing near HBias=40 kA/m. As H3 is increased, domain wall motion occurs, decreasing the HBias required to maximize the properties by reducing stress-induced anisotropy