Effective magnetostriction and magnetomechanical coupling of terfenol-D composites

Abstract

Epoxy and glass matrix Terfenol-D composites have been produced by using a cold and hot compression-molding technique, respectively. The static and dynamic magnetic and magnetomechanical properties of samples with a volume fraction Vf in the range of 10% to 82% have been investigated as functions of bias field, frequency, and ac drive field. The epoxy composites have a greater saturation magnetostrain than the glass composite with the same Vf. The elastic modulus of the epoxy composites is dominated by that of the matrix, Em. Increasing the value of Em reduces the measured magnetostriction λc of the composites. A model, based on the strain related energy equilibrium, has been developed to describe the experimental results for Vf and Em dependences of λc and the magnetomechanical coupling coefficient k33. It is concluded that an optimum k33 value can be obtained by choosing a matrix with an appropriate elastic modulus.