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The work is aimed at the development of a new sintered aluminium alloy with a low temperature coefficient of linear expansion that opens fundamentally new opportunities for solving the modern needs of domestic machinebuilding and instrument-making enterprises in light materials with special physical properties. Phase composition, structure and properties of cast aluminium alloys Al-Si-Ni with different contents of silicon and nickel, as well as powders obtained by grinding rapidly-quenched metal ribbons of these alloys in a high-energy ball mill are studied using various methods of structural analysis. The obtained values of the coefficient of linear expansion of the studied alloys in the cast state are significantly lower than those of pure aluminium, and they amount to = (11-15) 10-6 K-1. The method of obtaining a powder of a rapidly-crystallized alloy by manufacturing a rapidly-quenched metal ribbons using melt spinning followed by its dispersion in a high-energy ball mill is proposed for the fabrication of finely-dispersed powder and subse- quent hot pressing. [ABSTRACT FROM AUTHOR]

The literature data on the problem of modification of the structure and properties of the Fe-based rapid-quenched alloys by various methods of severe plastic deformation (SPD) are reviewed. The SPD methods such as Bridgman cell torsion, ball-mill processing and high-frequency shock treatment as well as their advantages and disadvantages are considered. By examples of a large number of amorphous Fe-based alloys, the influence on their structure and properties of each of the considered SPD methods is analysed. Based on the obtained data, the mechanism of deformation nanocrystallization of amorphous alloys is proposed. [ABSTRACT FROM AUTHOR]

Decomposition of supersaturated solid solution of aluminium alloys alloyed with Sc and Zr have been studied in the work. The binary hypereutectic Al-Sc alloys, hyperperitectic Al-Zr alloys and ternary Al-Sc-Zr alloys were chosen. Alloys were obtained by the melt-spinning. Melts were quenched from temperatures of T = 1000 °C and T = 1400 °C. The crystallization of anomalously supersaturated solid solution (Tquen: = 1400 °C) or the crystallization with the formation of -fan- structure (Tquen: = 1000 °C) are possible. The decomposition of anomalously supersaturated solid solution is continuous, with the precipitation of nanosized spherical Al3X (X = Sc, Zr) particles. The loss of thermal stability of Al-Sc alloys is due to the loss of coherence of the strengthening Al3Sc phase. In Al-Zr alloys the loss of strength is due to the formation of a stable tetragonal DO23-ordered Al3Zr phase. After co-alloying of Al by Sc and Zr a bimodal grained structure was observed for the hypereutectic ternary alloy (Tquen: = 1400 °C). Nanosized grains of 50-60 nm were present on the boundaries of 1-2 μm large-sized grains. Transmission electron microscopy shows the formation of nanocomposite Al3Zr/Al3Sc particles. The formation of Al3Zr shell changes the nature of the interfacial fit of the particle with the matrix and slows down the decomposition during the coalescence. [ABSTRACT FROM AUTHOR]

The oxidation of aniline is studied by the potentiodynamic method on an electrode of an amorphous metallic alloy AlNiY and the results are compared with the analogous data on a polycrystalline aluminum electrode. The aniline oxidation and, correspondingly, the polyaniline deposition are shown to proceed more actively on the contact side of the amorphous metal alloy AlNiY electrode. The morphology of synthesized polyaniline films is studied on both sides of the working electrode. It is found that the polyaniline layer structure is to the large extent granulated on the contact side and smooth on the external side. [ABSTRACT FROM AUTHOR]

The X-ray diffraction method is used to study the short-range ordering of Al87Y5Ni8, Al87Gd5Ni8, Al87Y4Gd1Ni8, Al87Y4Gd1Ni4Fe4, and Al87Gd5Ni4Fe4 amorphous alloys. The structural factors are obtained and the pair correlation functions are computed. The principal structural parameters are analyzed. It is shown that the investigated amorphous alloys are characterized by the topological short-range order based on the close-packed structure of aluminum and Al3Y(Gd)-and Al3Ni(Fe)-type chemical short-range ordering. It is discovered that the replacement of Y atoms with Gd atoms and Ni atoms with Fe atoms weakly affects the topology of the atomic distribution of the aluminum matrix and leads to changes in the character of chemical ordering. This affects the degree of short-range microhomogeneity of the short-range ordering and the dimensions of structural units. [ABSTRACT FROM AUTHOR]

The thermodynamic characteristics of annealed specimens of Fe80.0Si6.0B14.0 amorphous metal alloys are obtained according to the data of measurements of instantaneous changes in the electromotive force. It is shown that the proposed method of measurements is more sensitive to changes in the structure and phase composition of amorphous-metal electrodes than the X-ray methods. [ABSTRACT FROM AUTHOR]

Microstructures of dynamically undercooled (melt spun) Fe-base alloys characterized by a post-dendritic needle-like growth morphology were shown to be essentially identical to those of bulk undercooled samples with Δ T > 190–200 K. Nonequilibrium crystallization is accompanied by the formation of internal stresses and defects which can lead to relaxation processes (polygonization, recrystallization) during the cooling procedure changing the asquenched microstructure. The mechanism and degree of these transformation processes are determined by the level of frozen-in microstresses, the cooling rate in the solid state, and the lattice structure of the alloys. [ABSTRACT FROM AUTHOR]