Analysis of both nanocrystallization and creep-induced anisotropy kinetics in Fe–Si–B–Cu–Nb alloys

Amorphous-nanocrystalline transformation in Fe73.5Si15.5B7Cu1Nb3 is investigated by magnetostriction (λs) and creep-induced anisotropy measurements. Crystalline volumetric fraction, p, is checked by X-ray diffraction. The temperature dependence of magnetostriction is consistent with Herzer’s dilution law. Kinetics are well described using the Johnson–Mehl–Avrami (JMA) approach with the activation energy equal to 4.5 eV. Creep-induced anisotropy is interpreted within the framework of the so-called “back stress” model. Based on these results, optimal crystalline fraction can be achieved by flash annealing. TEM imaging reveals homogeneous nanocrystallization.