Dynamic magnetoelastic properties of epoxy-bonded terfenol-D particulate composite with a preferred [112] crystallographic orientation

The dynamic magnetoelastic properties of a [112]-oriented magnetostrictive composite comprising 0.49 volume fraction of needle-shaped, [112]-oriented Terfenol-D particles and Spurr epoxy were investigated as a function of magnetic bias field. These properties included elastic moduli (E₃^H and E₃^B), dynamic strain coefficient (d₃₃), and magnetoelastic coupling coefficient (k₃₃). A randomly oriented composite with 0.51 volume fraction of irregular-shaped, ball-milled Terfenol-D particles was also prepared and characterized for comparison. It was found that the [112] preferential particulate orientation increases non-180° domain-wall motion in the [112]-oriented composite, resulting in maximum negative-ΔE,d₃₃, and k₃₃ values of about 10%, 5.5 nm/A, and 0.34, respectively. These are the largest property values reported as yet for magnetostrictive particulate composites, being up to 67% larger than the randomly oriented composite and approach to 65% of the monolithic Terfenol-D.