Furnace and current annealing of the amorphous Fe72Cu1Nb4.5Si13.5B9 alloy

Specimens of the amorphous Fe72Cu1Nb4.5Si13.5B9 alloy have been nanocrystal lized by furnace (FA) and current (CA) annealing and analyzed by simultaneo us small-angle (SAXS) and wide-angle (WAXS) x-ray scattering using the beam -line 5.2L at Elettra Synchrotron Source, Trieste. The analysis has been ca rried out also dynamically on untreated samples current heated in situ. Sig nificant differences in the SAXS regime have been observed between the FA a nd CA samples having the same amount of nanocrystallization as determined f rom previous WAXS and Mossbauer measurements. These differences can be attr ibuted to a lower contrast of the nanocrystallites in the CA samples as com pared to FA samples. The Mossbauer spectra show that in FA and CA samples t he nanocrystalline grains consist of a nonstoichiometric partially disorder ed Fe3Si phase, and indicate the presence of boron atoms in the nanocrystal s of CA samples. This is in agreement with the lower contrast found by SAXS and implies a lower segregation of boron atoms and/or of borides at the bo undaries of nanocrystallites of CA samples, accounting for their lower brit tleness. (C) 2000 American Institute of Physics. [S0021-8979(00)77608-0].