Large magnetostriction in Terfenol-D particulate composites with preferred [112] orientation

Abstract

Terfenol-D particulate composites have been fabricated with and without a preferred crystal orientation of the particles. A 25% volume fraction polymer matrix composite was fabricated in a magnetic field using geometric anisotropy to orient needle shaped particles with long axis [112] orientation along the length of the composite. Results demonstrate that the magnetostriction of a [112] oriented particle composite saturates near 1600 ppm. This is a significant increase when compared to composites without preferential orientation (1200 ppm). The oriented particle composite exhibits the largest reported magnetostriction for a particulate composite material. The magnetization-strain measurements indicate that the strain in the oriented composite is proportional to the (lambda) <SUB>112</SUB> saturation magnetostriction while the non-oriented composite is proportional to the polycrystalline saturation magnetostriction, (lambda) <SUB>pc</SUB>. In addition, the fields necessary for equivalent magnetostriction in the oriented particle composite are reduced when compared to the non-oriented composite, though both require higher fields than commercially available monolithic Terfenol-D.