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

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 magneto striction 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 (112) saturation magnetostriction while the non-oriented composite is proportional to the polycrystalline saturation magnetostriction, lambda (pc). 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.