Analysis of nano crystallization process in Fe73.5Cu1Nb3Si15.5B7 alloys by cumulant expansion of EXAFS

Amorphous-nanocrystalline transformation in Fe73.5Cu1Nb3Si15.5B7 is investigated by extended X-ray absorption fine structure (EXAFS) and analysed by the cumulant method, which allows a refined study of parameters that are able to describe the local structure during the nanocrystallization. The nearest-neighbour interatomic distance and coordination number have been determined for Fe3Si and Fe; these elucidate the nanocrystallization in two stages. The first stage revealed the formation of DO3 nanocrystals and the second stage show evidence of a disordered Fe-rich interfacial region formed around the DO3 nanograins. Thus the cumulant analysis of EXAFS is sensitive to the different crystalline fraction arising from annealing at various temperatures. (c) 2005 Elsevier B.V. All rights reserved.