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Information × Registration Number 0212U004238, 0109U002087 , R & D reports Title Nanostructuring of amorphous metallic alloys based on aluminium as a factor of changing their physical-chemical properties popup.stage_title Head Kotur Bogdan Jaroslavovych, Registration Date 31-01-2012 Organization Ivan Franko National University of Lviv popup.description2 The structure of the as-cast amorphous metallic alloys (AMA) Al87R5M8 (R = Y, Gd, Dy; M = Ni, Fe) is characterized by short-range order based on the structure of aluminum and binary intermetallic compounds (IMC) RAl3 and M-Al. It is shown that partial replacement of Y atoms by Gd or Dy reduces the thermal stability of alloys. It was found that initial AMA Al87R5Ni8 and Al87Y4R1Ni8 (R = Y, Gd, Dy) crystallize in three stages. The first two stages correspond to the formation of nanocrystals of Al(R). The third stage of crystallization is concerned with formation of IMC R3Ni5Al19 (R = Y, Gd, Dy) with the Gd3Ni5Al19-type structure. Partial replacement of Ni atoms by Fe slows diffusion of atoms at all stages of crystallization, which leads to increasing of thermal stability. Crystallization of these alloys occurs in three stages with the formation at the final stage IMC RM4Al8 (R = Y, Gd, Dy; M = Fe, Ni), with CeMn4Al8-type structure. Complete replacement of Ni by Fe increases the thermal stability and changes the character of crystallization AMA Al87Dy5Fe8 (from three to five stages) with the formation of the metastable unidentified IMC. For all investigated AMA electrical resistance decreases with the partial replacement of Y by Gd or Dy, and increases with Ni substitution by Fe. Magnetic properties of AMS-based Al87Y5Ni8 indicate the formation of super paramagnetic clusters of Ni (containing ~ 50 atoms) of the total magnetic moment of approxomately 13.5 magneton Bohr. Doping of amorphous alloys by Gd leads to a reduction of the resulting magnetic moment of Ni-clusters. Partial substitution of Ni atoms by Fe does not change the magnetic structure of the AMA. It is shown that all investigated amorphous and nanostructured alloys have high corrosion resistance in 0.1 M aqueous solution of NaCl. Replacing Y by Dy leads to increasing and substitution of Y by Gd to reducing of corrosion resistance of alloys in comparison with the initial AMA. Substitution of Ni by Fe in the Al87Gd5Ni8 amorphous alloy reduces corrosion currents, which lead to conclution about higher corrosion resistance of Al87Gd5Ni4Fe4 AMA. Change the corrosion resistance of the studied AMA also connected with the formation of protective surface oxide films of different densities. Product Description popup.authors Бойчишин Лідія Михайлівна Ковбуз Мирослава Олексіївна Котур Богдан Ярославович Міка Тарас Мирославович Мудрий Степан Іванович popup.nrat_date 2020-04-02 Close