Direct control of medium range order in a Ni modified Finemet-type alloy

Citation
E. Illekova et al., Direct control of medium range order in a Ni modified Finemet-type alloy, J NON-CRYST, 287(1-3), 2001, pp. 167-170
Citations number
11
Categorie Soggetti
Apllied Physucs/Condensed Matter/Materiales Science
Journal title
JOURNAL OF NON-CRYSTALLINE SOLIDS
ISSN journal
00223093 → ACNP
Volume
287
Issue
1-3
Year of publication
2001
Pages
167 - 170
Database
ISI
SICI code
0022-3093(200107)287:1-3<167:DCOMRO>2.0.ZU;2-M
Abstract
Using continuous-heating differential scanning calorimetry (DSC) and X-ray diffraction, the planar-flow casted Fe54Ni20Cu1Nb3Si13B9 amorphous ribbons have been investigated. In the as-prepared alloy, a heating rate dependence of the crystallization kinetics differs from that of other finemet alloys. Namely, the ordered Fe-3 Si and Fe3NiSi1.5 phases crystallize simultaneous ly in one crystallization step via a viscous flow mechanism at heating rate s, w > 25 K min(-1). However, in the same material, the crystallization pro ceeds as a two-step transformation either after a > 20-min isothermal annea l at 663 K (which is 100 K less than the onset of the main transformation) or when applying a smaller heating rate, it, < 20 K min(-1). Then, the same phases crystallize separately in the first and second crystallization step s. The interpretation is based on the correlation between the change of bot h atomic transport mechanism and kinetics of the formation of two alternati ve crystalline phases and the topological Fe-Ni ordering in the sample duri ng the stage prior to the nucleation. (C) 2001 Elsevier Science B.V. All ri ghts reserved.