Specimens of the amorphous Fe72Cu1Nb4.5Si13.5B9 alloy have been nanocrystallized by furnace (FA) and current (CA) annealing and analyzed by simultaneous 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 carried out also dynamically on untreated samples current heated in situ. Significant differences in the SAXS regime have been observed between the FA and CA samples having the same amount of nanocrystallization as determined from previous WAXS and Mössbauer measurements. These differences can be attributed to a lower contrast of the nanocrystallites in the CA samples as compared to FA samples. The Mössbauer spectra show that in FA and CA samples the nanocrystalline grains consist of a nonstoichiometric partially disordered Fe3Si phase, and indicate the presence of boron atoms in the nanocrystals 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 boundaries of nanocrystallites of CA samples, accounting for their lower brittleness.

Furnace and current annealing of the amorphous Fe72Cu1Nb4.5Si3.5B9 alloy

PRINCIPI, GIOVANNI;MADDALENA, AMEDEO;
2000

Abstract

Specimens of the amorphous Fe72Cu1Nb4.5Si13.5B9 alloy have been nanocrystallized by furnace (FA) and current (CA) annealing and analyzed by simultaneous 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 carried out also dynamically on untreated samples current heated in situ. Significant differences in the SAXS regime have been observed between the FA and CA samples having the same amount of nanocrystallization as determined from previous WAXS and Mössbauer measurements. These differences can be attributed to a lower contrast of the nanocrystallites in the CA samples as compared to FA samples. The Mössbauer spectra show that in FA and CA samples the nanocrystalline grains consist of a nonstoichiometric partially disordered Fe3Si phase, and indicate the presence of boron atoms in the nanocrystals 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 boundaries of nanocrystallites of CA samples, accounting for their lower brittleness.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11577/2471538
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