Pinning of nanocrystals growth at Fe-Ni-B amorphous alloy crystallization: Atom probe investigations

摘要

The crystallization processes in Fe50Ni33B17 amorphous alloy have been investigated by transmission electron microscopy (TEM) and a three dimensional atom probe (3DAP). The gamma-Fe,Ni FCC crystals, 25 nm in size, were found in the amorphous alloy annealed at temperatures ranging 360-400 degrees C for 1 h. TEM demonstrates that the nanocrystals growth stops as the temperature rises. The formation of an amorphous layer enriched in boron at the border of gamma-Fe,Ni nanocrystals responsible for the pinning of nanocrystals size was observed by 3DAP. The composition of an amorphous barrier by 3DAP was found to be Fe50Ni29B21. It was proposed that this composition reveals higher crystallization temperature, which is the reason of pinning nanocrystals growth. (C) 2015 Elsevier B.V. All rights reserved.