The amorphous phase decomposition in Fe-based alloys after severe plastic deformation

Danila V. Matveev 1G. E. Abrosimova 1A. S. Aronin 1S. V. Dobatkin 2O. G. Rybchenko 1E. V. Tatiyanin 2,3I. I. Zverkova 1

1. Russian Academy of Sciences, Institute of Solid State Physics, Chernogolovka 142432, Russian Federation
2. Russian Academy of Sciences, Baikov Institute of Metallurgy and Material Science (IMET RAS), 49 Leninsky prospect, Moscow 119991, Russian Federation
3. Institute for High Pressure Physics, Russian Academy of Sciences, Troitsk 142092, Russian Federation

Abstract

Fe-based amorphous alloys show high magnetic properties. Last years metallic glasses have attracted the interest as precursors for production of nanocrystalline state. Nanocrystalline structure created by primary crystallization of melt-spun amorphous Fe-based ribbons exhibits excellent soft magnetic properties. Small addition of Cu and Nb deteriorate potential properties of nanocrystalline Fe-Si-B alloy. However nanocrystalline structure does not form at the crystallization of Fe-Si-B and Fe-B alloys at heating. Nowadays, formation of nanocrystalline structure was found to occur under severe plastic deformation [1]. Recently we have formed nanocrystalline structure in amorphous Fe81В13Si6 alloy by high pressure torsion at different temperatures. The nanocrystalline structure was found to form at achievement of definite strain. The phase composition, crystal size, morphology and distribution of crystals in the sample depend on a strain and treatment temperature. The minimal size of the obtained crystals is 5-10 nm. In this work we try to form the nanocrystalline structure by high pressure treatment of amorphous Fe80B20 and Fe84B16 alloys.
Amorphous Fe80B20 and Fe84B16 alloys were prepared by melt quenching. The samples were exposed to pressure of 4 and 6 GPa at room temperature in a toroid-type chamber using hexagonal BN as pressure transmitting medium. Structure of the samples was studied by X-ray diffraction and transmission electron microscopy. X-ray diffraction patterns of as-prepared samples were typical for metallic glasses. A position of first diffuse halo corresponds to 2 = 57.09 for Fe84B16 and 2 = 57.28 for Fe80B20 (FeK radiation). The shift of the position of first diffuse maximum points to a change of a radius of first coordination sphere with boron concentration. After high pressure treatment the shape of diffuse peak slightly changes and it could be described only as a sum of two Gauss functions with the first of them corresponding to amorph
[ABSTRACT TRUNCATED TO 2000 LETTERS]

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Presentation: poster at E-MRS Fall Meeting 2005, Symposium I, by Danila V. Matveev
See On-line Journal of E-MRS Fall Meeting 2005

Submitted: 2005-04-26 13:20
Revised:   2009-06-07 00:44
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