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

Abstract

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 ( H Bias=5–140 kA/m) and drive ( H 3=1–9 kA/m) fields. These properties include elastic moduli ( E 3 H and E 3 B ), dynamic relative permeability ( μ r33 T ), dynamic strain coefficient ( d 33), magnetomechanical coupling coefficient ( k 33), and the ratio of the dynamic strain coefficient to the dynamic susceptibility ( d 33/ χ 33). The changes in the composite properties with applied fields can be explained in terms of domain wall motion followed by saturation. At a low H 3 of 1 kA/m, the available non-180° domain state created by residual compressive stresses in the composites results in negative-ΔE, d 33, k 33, and d 33/ χ 33 maximizing near H Bias=40 kA/m. As H 3 is increased, domain wall motion occurs, decreasing the H Bias required to maximize the properties by reducing stress-induced anisotropy.