Local atomic and magnetic structures of nanocrystalline [Fe.sub.75][Cr.sub.10][B.sub.15] alloy

• Published in: Physics of the solid state 2012-09, Vol.54 (9), p.1790
• Main Authors: Pokatilov, V.S, Dmitrieva, T.G, Pokatilov, V.V, D'yakonova, N.B
• Format: Article
• Language: English
• Subjects: Annealing; Chromium; Diffraction; Metallic glasses; Specialty metals industry; X-rays
• ISSN: 1063-7834; 1090-6460
• DOI: 10.1134/S1063783412090259

The crystal, local atomic and magnetic structures of [Fe.sub.75][Cr.sub.10][B.sub.15] alloys annealed at 440- 473°C for 5 min have been studied using X-ray diffraction and [sup.57]Fe Mossbauer spectroscopy. At the annealing temperature [T.sub.a] = 440°C, nanocrystals of the α-Fe phase (~1%) precipitate in the amorphous matrix of the alloy. The complete crystallization of the amorphous alloy occurs at [T.sub.a] = 473°C with the formation of α- Fe nanocrystals 26 ± 2 nm in size and nanocrystals of tetragonal boride t-[Fe.sub.3]B 47 ± 2 nm in size. It has been found that chromium atoms are located in nanocrystals of the α-Fe and y-[Fe.sub.3]B types. The distribution functions of hyperfine fields in the nanocrystalline [Fe.sub.75][Cr.sub.10][B.sub.15] alloy reconstructed from the Mossbauer spectra (at [T.sub.a] = 473°C) show that there are three allowed states of iron atoms in the α-Fe phase and three equally probable crystallographic nonequivalent states of iron in the t-[(Fe,Cr).sub.3]B phase. The chromium concentration x in the α-Fe(Cr) phase is found to be ~10 at %. The substitution of chromium atoms for iron atoms in t-[Fe.sub.3]B substantially decreases local magnetic moments of the iron atoms.