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[en] It is demonstrated that, for a single composition, the phase equilibria of multi-component alloy systems can be represented in a simple two-dimensional diagram. In this ''stability diagram'', the atom fraction of each phase is represented as a function of temperature. Examples are given for simple two and four component systems
[en] A model describing the spectral blueshift of the quaternary alloy InxGa1−xNyAs1−y (x<0.4 and y≤0.04) caused by the In–N clusters after annealing is developed by modifying the band-anticrossing (BAC) model. In the modified BAC model, we consider the effect of the added In–N clusters after annealing on the parameters in the band anticrossing model. It is found that the variation of the N level can be considered to be proportional to the variation of the average number of the nearest-neighbor In atoms per N atom, and the variation of the coupling interaction between the N level and the Γ conduction band is determined by the added In-N bonds and the In content. The obtained results are in agreement well with the experimental data. It is very helpful to explain the essence of the blueshift caused by annealing
[en] Ruthenium (Ru) is one of the more abundant fission products (FPs) both in fast breeder reactors and thermal reactors. Post irradiation examinations (PIE) show that both 'the white metallic phase' (MoTc-Ru-Rh-Pd) and 'the other metallic phase' (U(Pd-Rh-Ru)3) are present in spent nuclear fuels. To describe this quaternary system, binary subsystems of uranium (U) with Pd, Rh, and Ru are necessary. Presently, only the U-Ru system has been thermodynamically described but with some problems. As part of research on U-Ru-Rh-Pd quaternary system, an improved consistent thermodynamic model describing the U-Ru binary phase diagram has been obtained. (author)
[en] The influence of 1.1 wt% tin additions on the precipitation hardening of Cu-11 wt% Ni-20 wt% Zn alloy was studied by Differential Scanning Calorimetry (DSC), microhardeness measurements and High Resolution Transmission Electron Microscopy (HRTEM). The calorimetric curves, in the range of temperatures analyzed, show the presence of two exothermic reactions in the ternary alloy, associated to the short-range-order development assisted by migration of excess vacancies. On the other hand, one exothermic and one endothermic reaction are observed in the quaternary alloy, associated to the formation and dissolution of Cu_2NiZn precipitates, respectively. It has been show that an addition of 1.1% tin plays an important role in the formation of Cu_2NiZn precipitates, responsible for the precipitation hardening of the ternary alloy. (Author)
[en] The cohesive energy, bulk modulus, elastic constants, pressure derivative of bulk modulus and pressure derivative of elastic constants for Inx Ga1-x Ny As1-y semiconducting quaternary alloys have been investigated based on pseudopotential formalism. A reasonable agreement of presently investigated numerical data with the available experimental data and other such theoretical values has been observed. (author)
[en] The partitioning behavior of the elements W, Mo, Re, Ru and Ir of three experimental nickel-base superalloys was investigated. For comparative studies ternary and quaternary alloys were produced and analyzed. The distribution coefficient of Re is shown to be a function of composition. Ru and Ir do not affect the partitioning behavior of Re
[en] Highlights: ► New Mg-based alloys in the Mg–Ag–Ca–Cu system with high glass forming ability. ► Critical amorphous castings sizes of up to 5 mm using copper mould casting. ► Glassy alloys were discovered/predicted using a new topological approach. ► Predicted composition range corresponds with regions of high glass forming ability. - Abstract: A range of new magnesium-based bulk metallic glasses (BMGs) from the Mg–Ag–Ca, Mg-Cu-Ca ternary and Mg–Ag–Cu–Ca quaternary alloy systems have been discovered using the effective radius ratio method. These alloys are located over a broad composition range from (at.%): Mg – 38–76, Ag – 0–38, Cu – 0–36 and Ca – 7–27, some of which are located far from ternary eutectic reactions. Here, we report the alloy design method, critical casting size and thermophysical properties of these new BMGs.
[en] Planar melt crystallization is used to grow single crystals of Cd-Mg-Mn-Te quaternary alloys along the pseudobinary sections Cd0.75−xMgxMn0.25Te, Cd0.75−xMg0.25MnxTe, and Cd1−2xMgxMnxTe. The first photosensitive structures, i.e., In/CdMgMnTe Schottky barriers, are fabricated within each indicated single-crystal section. The spectral dependences of the relative quantum efficiency of photoconversion are measured, and the broadband photosensitivity of the new structures is detected. Based on the spectral dependences of the photosensitivity, the nature of the meson transitions is discussed and the corresponding band gaps are determined. The applicability of grown single crystals of CdMgMnTe quaternary alloys to broadband photoconverters of optical radiations is ascertained.
[en] Interaction of arsenic chalcogenides with semiconducting compounds of A3B6 type, GaS in particular, was studied. The phase diagram of As2Te3-GaS system was plotted. It was established, that the given section is quasibinary cross-section of quaternary mutual Ga, As parallel S, Te system. The compound of 3 GaSxAs2Te3 composition forms according to peritectic reaction during As2Te3 interaction with GaS. The boundary of α-solid solutions, the length of which is 5 mol%GaS at room temperature was determined
[en] To calculate the criticality parameters of nuclear fuel solution systems, the many nuclide densities needed are generally estimated from density equations. Most of the equations for calculating the density of aqueous solutions containing the electrolytes HNO3-UO2(NO3)2-Pu(NO3)4, commonly called nitrate dilution laws are strictly empirical. They are obtained from a fit of assumed polynomial expressions on experimental density data. Out of their interpolation range, such mathematical expressions show discrepancies between calculated and experimental data appearing in the high concentration range. In this study, a physico-chemical approach based on the isopiestic mixtures rule is suggested. The behavior displayed by these mixtures was first observed in 1936 by ZDANOVSKII and expressed as: Binary solutions (i.e. one electrolyte in water) having the same water activity are mixed without any change in the water activity value. To address this behavior, RYAZANOV and VDOVENKO in 1965 developed a set of basic thermodynamic expressions concerning enthalpy, entropy, volume of mixtures, activity and osmotic coefficient of the components. In particular, a very simple equation for density is obtained from the volume mixture expression depending on only two physico-chemical variables: - concentration of each component in the mixture and in their respective binary solutions having the same water activity as the mixture, - density of each component respectively in the binary solution having the same water activity as the mixture. Hence the calculation needs the binary data (water activity, density and concentration) on each component at the same temperature as the mixture. Such experimental data are widely published in the literature and are available for nitric acid and uranyl nitrate. However, nitric acid binary data show wide discrepancies between the different authors and need to be reviewed. This extensive work was done by Charrin for his PhD. In this work, density data on uranyl nitrate binary solutions have been tabulated by incorporating recent experimental data with older published tables. Due to the irreversible formation of colloidal or polymeric species leading to precipitation, plutonium(IV) nitrate binary solution does not exist. Nevertheless, binary data on 'fictive' binary solutions were determined by Charrin, using Zdanovskii's mixture rule. The validity of this equation was checked on experimental density data for HNO3-UO2(NO3)2-H2O ternary solutions available in the literature as shown in Figure 1. The Ryazanov-Vdovenko equation was also validated on new density data for HNO3-UO2(NO3)2-Pu(NO3)4-H2O  quaternary mixtures. The difference between experimental and estimated values is always less than 0.4 percent, compared to the mean deviation of 0.6 per cent obtained with Sakurai-Tachimori mathematical equation. (authors)