GRAIN-GROWTH PROCESSES IN A NANOCRYSTALLINE FE74.5SI13.5B9NB3 ALLOY

Grain growth processes in a nanocrystalline Fe74.5Si13.5B9Nb3 alloy, w hich was formed from its amorphous alloy precursor by crystallization, were investigated by differential scanning calorimetry (DSC) and X-ra y diffraction (XRD) techniques. Upon heating the alloy at constant hea ting rates, two exothermal peaks are observed, the first of which main ly originates from the grain growth of Fe3Si and Fe3B crystallites and the second mainly from Fe23B6 and FeNbB grain growth. The activation energy for grain growth of Fe3Si and Fe3B phase is calculated by means of grain growth temperature and heating rate using the Kissinger equa tion. The DSC and XRD measurement results indicate that the nanophases in the alloy are relatively stable, presumably due to the addition of Nb element, which suppresses the crystallite growth.