Two-stage nanostructural formation process in Fe-Nb-B soft magnetic alloys

Abstract

The nanostructural formation kinetics in a soft magnetic Fe 80Nb6B14 alloy have been investigated by means of differential scanning calorimetry, thermogravimetric analysis and transmission electron microscopy. Unlike nanocrystalline Fe-Zr-B soft magnetic alloys, where the nanocrystallite formation is governed mostly by a nucleation and growth mechanism, the nanostructural formation mechanism in the Fe-Nb-B alloy shows a change in the fraction transformed range 0.1-0.2. The first- and second-stage nanostructural formation processes have been described by the nucleation and growth and grain-growth models, respectively. This two-stage nature in the nanostructural formation kinetics can be attributed to a high population density of the primary bcc nuclei.© 1995 American Institute of Physics.