Structures and Magnetostriction of a Tb-Dy-Fe System for Casting Polycrystalline Alloys

Abstract

The structures and magnetostrictive properties of Tb_xDy_1-xFe_1.9 (x = 0.25, 0.30, 0.35, 0.50, 0.70) alloys prepared by a conventional induction melting and casting method were investigated. These alloys had a columnar structure in the thermal flow direction, and their grain size decreased with increasing Tb content. The magnetic and magnetostrictive properties reflected the magnitude of the magnetocrystalline anisotropy and the saturation magnetostriction. The result is related to the Tb/Dy ratio of alloys. The magnetostriction increased to more than 1500 ppm by annealing, and with decreasing the lattice spacing of the Laves phase. Grain growth was observed simultaneously.