Orientation, morphology and magnetostriction of a heat-treated <110> oriented TbDyFe alloy

摘要

<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 deg C has been earned 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 1000 deg C is proper for the present <110> oriented TbDyFe alloy.