Dynamic magnetomechanical behavior of Terfenol-D/epoxy 1-3 composite

This paper presents an experimental investigation of the dynamic behavior of a 1-3 type magnetostrictive composite, with emphasis on the evaluation of fundamental material properties pertinent to device design. The fabricated 1-3 magnetostrictive composite comprises 51% volume fraction of Terfenol-D particulates embedded and magnetically aligned in a passive epoxy matrix. The dynamic magnetomechanical properties of the composite are measured as functions of bias field (5-140 kA/m), drive field (1-9 kA/m), and frequency (1-100 kHz). These properties include Young's moduli at constant magnetic field strength (E3H) and at constant magnetic flux density (E3B), magnetomechanical coupling coefficient (k33), dynamic relative permeability (μr33), dynamic strain coefficient (d33), mechanical quality factor (Qm), and the ratio of the dynamic strain coefficient to the dynamic susceptibility (d33/χ33). Dependence of material properties on applied fields and frequency is observed with no evidence of eddy current losses. The observed eddy current effect agrees with the prediction of classical eddy current theory. This suggests that the composite can provide superior high-frequency performance as compared to monolithic Terfenol-D and laminated Terfenol-D systems. Implications for high-frequency applications of the material to resonance devices are also described.