Thermally induced crystallization of Fe73.5Cu1Nb3Si15.5B7 amorphous alloy

0431855 - ÚFM 2015 RIV NL eng J - Journal Article
Blagojević, V. A. - Vasić, M. - David, Bohumil - Minić, Dušan M. - Pizúrová, Naděžda - Žák, Tomáš - Minić, Dragica M.
Thermally induced crystallization of Fe73.5Cu1Nb3Si15.5B7 amorphous alloy.
Intermetallics. Roč. 45, FEB (2014), s. 53-59. ISSN 0966-9795. E-ISSN 1879-0216
R&D Projects: GA MŠMT 1M0512; GA ČR GA106/08/1440
Grant - others:Ministry of Education and Science of Serbia(RS) 172015
Institutional support: RVO:68081723
Keywords : metallic glasses * microstructure * thermal stability
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 2.131, year: 2014

Thermally induced crystallization of Fe73.5Cu1Nb3Si15.5B7 amorphous alloy occurs in two well-separated stages: the first, around 475 degrees C, corresponds to formation of alpha-Fe(Si)/Fe3Si and Fe2B phases from the amorphous matrix, while the second, around 625 degrees C, corresponds to formation of Fe16Nb6Si7 and Fe2Si phases out of the already formed alpha-Fe(Si)/Fe3Si phase. Mossbauer spectroscopy suggests that the initial crystallization occurs through formation of several intermediate phases leading to the formation of stable alpha-Fe(Si)/Fe3Si and Fe2B phases, as well as formation of smaller amounts of Fe16Nb6Si7 phase. X-ray diffraction (XRD) and electron microscopy suggest that the presence of Cu and Nb, as well as relatively high Si content in the as-prepared alloy causes inhibition of crystal growth at annealing temperatures below 625 degrees C, meaning that coalescence of smaller crystalline grains is the principal mechanism of crystal growth at higher annealing temperatures. The second stage of crystallization, at higher temperatures, is characterized by appearance of Fe2Si phase and a significant increase in phase content of Fe16Nb6Si7 phase. Kinetic and thermodynamic parameters for individual steps of crystallization suggest that the steps which occur in the same temperature region share some similarities in mechanism. This is further supported by investigation of dimensionality of crystal growth of individual phases, using both Matusita-Sakka method of analysis of DSC data and texture analysis using XRD data.
Permanent Link: http://hdl.handle.net/11104/0236450