Magnetostriction and crystallizaation of a Fe-Cu-Nb-Si-B alloy annealed in vacuum from 300 to 650 °C

The magnetostriction of Fe_73.5CU₁Nb₃Si_15.5B₇ metallic glass, annealed in a vacuum for l h at temperatures from 300 to 650 °C, was measured using a strain gauge method. The maximum values of the magnetostriction coefficient for technical saturation (at Hmax = ~2.9 kA/m) slowly decreased from approximately 25 ± 2 × 10⁻⁶ after annealing at 300 °C, to approximately 21 ± 2 × 10⁻⁶ after annealing at 560 °C, and rapidly to about 2 ± 2 X 10⁻⁶ after annealing at 600 °C. After annealing at 650 °C, the magnetostriction increased to about 6 ± 2 × 10⁻⁶. The decrease in the magnetostriction is connected with an increase in crystallization.