Orientation, morphology and magneto striction of a heat-treated (110) oriented TbDyFe alloy

<110> oriented rods of a TbDyFe magnetostrictive alloy have been successfully prepared by zone melting unidirectional solidification. A homogenization annealing for 4 h or 48 h at 1000 degreesC has been carried out in a quartz cylinder under Ar-2 protection after pumping to 2 x 10(-3) Pa. The preferred orientation, morphologies and magnetostriction of the TbDyFe rods with directional solidification or annealing have been investigated. The <110> preferred orientation remains unchanged after annealing. The net-shaped pseudo-eutectic rare earth phase becomes discontinued and spheroidal after annealing for 4 h and shows spheroidal shape without the net-shaped morphology after annealing for 48 h. The magnetostriction slightly decreased after annealing without pre-stress, but increased drastically with pre-stress. An obvious magnetostriction jump effect was observed in the annealed samples. A satisfactory magnetostrictive property of 1970 x 10(-6) was obtained under 15 MPa pre-stress after 4 h heat treatment without a further improvement for 48 h annealing, which indicates that the heat treatment for 4 h at 1000degreesC is proper for the present <110> oriented TbDyFe alloy. (C) 2003 Elsevier B.V. All rights reserved.