Phase structure investigations of the bulk glassy FeCoZrWB alloys
|Piotr Pawlik 1, Jozef Bednarcik 2, Katarzyna Pawlik 1, Jerzy J. Wysłocki 1|
1. Institute of Physics, Częstochowa University of Technology, Al. Armii Krajowej 19, Częstochowa 42-200, Poland
Changes of nanostructure with the cooling conditions were studied on ribbon samples of various thicknesses produced by melt-spinning and rod and tube samples of various diameters prepared by suction-casting technique for the Fe61Co10+xZr5W4-xB20 (were x=0, 2, 3 at.%) alloys.
Mössbauer spectra analysis for the amorphous rod, tube and ribbon samples allowed the determination of hyperfine parameters for the amorphous phase and showed its ferromagnetic ordering in as-cast state. The hyperfine field Bhf distributions calculated from the Mössbauer spectra, also indicated non-equivalent surroundings for the Fe atoms. Furthermore, dissimilar Bhf distributions were observed for samples produced by various rapid solidification methods. The glass transition temperature Tg, crystallization temperature Tx and melting temperature Tm were compared for all alloy compositions. Furthermore the activation energies for crystallization have been evaluated using the Kissinger’s equation for particular alloy composition from the DSC plots.
High-energy X-ray diffraction (XRD) measurements were performed using monochromatic synchrotron radiation of 112 keV (λ=0.110696 Ǻ) at undulator beamline PETRA 2 of synchrotron facility DESY/HASYLAB (Hamburg, Germany). The analysis of diffraction patterns revealed fully glassy structure for ribbon samples of all compositions investigated. In case of the bulk samples, some traces of crystallinity were detected for the rod samples of all compositions, due to lower cooling rates applied for processing bulk glassy samples. The low fraction of crystalline phase present in the rod samples was impossible to detect by conventional XRD equipment, therefore the synchrotron radiation is due to its advantages more preferred technique of studying the glass forming ability of the alloys. Similar studies of the thin walled tubes samples revealed their fully amorphous nature.
Work supported by the Polish Ministry of Science and Higher Education (grant: 3T08A 046 27)
Presentation: Poster at E-MRS Fall Meeting 2007, Symposium I, by Piotr Pawlik
See On-line Journal of E-MRS Fall Meeting 2007
Submitted: 2007-05-14 12:23 Revised: 2009-06-07 00:44
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