Development of Terfenol-D transducer material

Terfenol-D, Tb1-xDyxFe2 (x congruent to 0.7), is successfully used as a mag netostrictive transducer material for low-frequency applications. To extend the frequency range of magnetostrictive transducers into the high kHz and MHz range, new materials processing techniques must be developed to minimiz e eddy current losses. The method that has demonstrated the greatest potent ial to date is based on rapid solidification by melt spinning to obtain thi n strips of material. The objective of this program includes refining the c asting procedure to yield ribbons with the [111] direction oriented along t he length of the ribbon, with the (110) plane in the plane of the ribbon. T he crystallographic orientation of the Terfenol-D ribbons have been control led by varying the cooling rate of the melt-spinning process. The cooling r ates were controlled by a number of parameters in the melt-spinning process and ribbons have been obtained with an enhancement of the (110) plane para llel to the surface of the ribbon. Magnetostrictive measurements under tens ile stresses up to 3 MPa and magnetic fields up to 4 kOe yielded magnetostr ictive displacements of 850 x 10(-6). (C) 1998 American Institute of Physic s. [S0021-8979(98)25711-2].