Document Type

Patent

Publication Date

8-14-2001

Abstract

The present invention provides Terfenol-D alloys (“doped” Terfenol) having optimized performances under the condition of time-dependent magnetic fields. In one embodiment, performance is optimized by lowering the conductivity of Terfenol, thereby improving the frequency response. This can be achieved through addition of Group III or IV elements, such as Si and Al. Addition of these types of elements provides scattering sites for conduction electrons, thereby increasing resistivity by 125% which leads to an average increase in penetration depth of 80% at 1 kHz and an increase in energy conversion efficiency of 55%. The permeability of doped Terfenol remains constant over a wider frequency range as compared with undoped Terfenol. These results demonstrate that adding impurities, such as Si and Al, are effective in improving the ac characteristics of Terfenol. A magnetoelastic Grüneisen parameter, γme, has also been derived from the thermodynamic equations of state, and provides another means by which to characterize the coupling efficiency in magnetostrictive materials on a more fundamental basis.

Patent Number

US 6,273,965 B1

ISURF Reference Number

2051

Assignee

Iowa State University Research Foundation, Inc.,

Application Number

US 08/953,192

Date Filed

10-17-1997

Language

en

File Format

application/pdf

Share

COinS