Magnetostriction and structure characteristics of Co70Fe30 alloy prepared by directional solidification

In this work, 〈1 0 0〉 textured Co70Fe30 alloy was successfully prepared by directional solidification technique. The effect of heat treatment on magnetostriction and microstructure of Co70Fe30 alloy has been investigated. The Co70Fe30 alloy was annealed in argon atmosphere at 700 °C-900 °C for 9 days and then cooled to room temperature by slow cooling or quenching. The magnetostriction as large as 180 ppm has been achieved for the quenched samples when the annealing temperature is ranging from 820 °C to 860 °C. Structural analyses indicate that the large magnetostriction originates from precipitation of a nanoscale face-centered tetragonal (fct) phase embedded in a body-centered cubic (bcc) phase matrix.