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Structure of systems Al-TM-Si (TМ - Fe, Co, Ni) in liquid and amorphous-crystal state


Author: Muratov Oleksii Sergiyovych

Organization: National university of food technology


Scientific work is devoted to an experimental and a model investigation of the structure of ternary Al-(TM)-Si (ТМ - Fe, Co, Ni) and corresponding binary boundary Al-Si, Al-Fe, Fe-Si, Ni-Si metallic melts by means of X-ray diffraction method and a method of reverse Monte-Carlo, and a method of molecular dynamics for liquid Al and Si. The obtained structural models are analyzed by a statistical-geometrical Voronoi–Delaunay method. Scattering curves for Al-Fe-Si and Al-Co-Si melts are obtained for the first time in the Al-rich corner at temperatures above a liquidus. Competitive influence of atoms of Aluminum and Silicium is determined on forming of local structure of transition metals' atoms in the explored ternary melts. It is shown, that the quantitative content of atoms in polytetrahedral clusters in Al-Fe-Si melts is considerably larger than in Al-Co-Si and Al-Ni-Si melts, which is explained by more intensive interatomic interaction in Al-Co-Si and Al-Ni-Si melts and is caused the existence of elements of the directional interacting between unlike atoms. Prepeak on structural factor curves' of ternary melts identifies existence of middle-range order, which is caused by correlation between atoms of a transition metal as a part of polytetrahedral clusters of icosahedral type. For the first time it is displayed, that existence of feature on a temperature dependence of physical-chemical properties of liquid aluminum near 800 0С is caused the emergence of elements of tight non-crystalline packing of atoms in the form of polytetrahedral clusters of icosahedral type. It is explained, that a excrescence on high-angle shoulder of the first peak of a structural factor of liquid Si caused by existence of fluctuation bonds of a covalent type. Efficiency of usage of a micro-heterogeneous model is displayed at the analysis of structure of Al-Si and Fe-Si melts in a wide concentration range near to a liquidus and the chemical nature of the short-range order in Al-Fe, Fe-Si, Ni-Si melts is acknowledged. At tempering (~105 К/с) of melts of composition Al70TM10Si20 (ТМ - Fe, Co, Ni), it is formed amorphous-crystal ribbons which one contain polycrystalline aluminum and an amorphous component.

The results of the work published in 5 articles in professional foreign journals, which included in the database SCOPUS (total impact factor 7.304), and published 18 abstracts at scientific conferences with various levels.