"Nanocomposites and nanomaterials"  

Investigations of the structure of amorphous Fe-B-P-Nb-Cr alloys
Ye.I. Yarmoshchuk1, T.M. Mika2, V.K. Nosenko2, M.P. Semen`ko1
1 Taras Shevchenko National University of Kyiv, Faculty of Physics, 2 Acad. Glushkova ave., Kiev 03022, Ukraine.
E-mail: yevhenii_yarmoshchuk@outlook.com
2 G. V. Kurdyumov Institute for Metal Physics of the N.A.S. of Ukraine, 36 Academician Vernadsky blvd., Kiev 03142, Ukraine.

The actual process of nanocrystallization unlike to the question of the connection of the physico-chemical properties of amorphous and nanocrystalline ribbons with the structural state of their surface is much less studied. 
The structure of Fe-B-P-Nb-Cr amorphous metallic glasses produced by a melt spinning technique was investigated. Using SAXS analysis [1] the size distributions of inhomogeneities in the samples were determined in both as‑quenched state and after heat treatment. In a result of SAXS researches it was shown that after the heat treatment the distribution of nanocrystalline inclusions in the alloys by size considerably decreases. After heat treatment predominate inhomogeneities with dimensions of about 4‑8 nm.
The surfaces and the cracks of amorphous Fe-B-P-Nb-Cr alloys in as‑quenched state and after heat treatment at 620-750 K, depending on the alloy, were investigated. Unexpected surface phenomena were observed during SEM studies. Using high-resolution SEM, the spherical nano-sized formations (hills) on the free surface of the ribbons were discovered. They were present for all the studied alloys except of S‑3, which was distinguished by the smallest content of metalloids. Formations size distribution after heat treatment varies depending from the alloy content. The S-3 alloy demonstrates very small (dispersed) structure after heat treatment. The SEM images of the cracks shows that the alloys in the initial state demonstrates “vein pattern” structure that indicates about the predominantly plastic nature of the destruction. After heat treatment, it is possible to observe a layered nanostructure of the crack surface relief, that describe the flow during the destruction of the ribbon with reduced characteristic transverse dimensions.

1.	Bressler I., Pauwb B. R., Thunemann A. F. McSAS: software for the retrieval of model parameter distributions from scattering patterns. // J. Appl. Cryst.-2015.-48.-P. 962–969.