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A four-dimensional (4D, in concentration–temperature coordinates) computer model of the isobaric phase diagram of uranium, sodium, magnesium, and plutonium chlorides, as well as four three-dimensional (3D) computer models of the phase diagrams of the ternary systems forming it, has been constructed. The technology of assembling a 4D model of 46 hypersurfaces and 17 phase regions was used in the design. The obtained 4D model of the UCl3–NaCl–MgCl2–PuCl3 phase diagram makes it possible to visualize a four-dimensional object as a whole (with all its hypersurfaces and phase regions) by any arbitrarily given 2D and 3D sections, as well as it is able to reproduce published (experimental or thermodynamically calculated) 2D sections. The scope of application of the results of the work is the development of materials for fuel components of fourth-generation molten salt reactors and pyrochemical recycling of spent fuel rods. For the first time, a comprehensive, complete description of phase diagrams composed of uranium, plutonium, sodium, and magnesium chlorides has been obtained. [ABSTRACT FROM AUTHOR]

A spatial (3D) computer model of an isobaric phase diagram of the LiCl–PrCl3–KCl system was designed. The model was assembled of 66 surfaces and 27 phase regions, of which 31 surfaces and 14 phase regions degenerate to verticals or vertical planes because of the limited solubilities of the initial chlorides and their compounds. Published experimental isothermal sections and thermoanalytical curves for 33 salt melts were used to improve the quality of the 3D model. The results can be used to improve the molten-salt refining technology of nuclear fuel waste. [ABSTRACT FROM AUTHOR]

A computer 3D-model was presented for the isobaric phase diagram of the ZrO2–SiO2–Al2O3 system with the formation of the ZrSiO4 and Al6Si2O13 compounds. Its geometric structure was derived through the sequential construction of a scheme of phase reactions, including all polymorphic transitions in the subsolidus and the rearrangement of the interaction of binary compounds, as well as zirconium and aluminum oxides; its transformation into a scheme of uni- and invariant states in the tabular and graphical (3D) forms; and the construction of a prototype and its transformation into a spatial model of the phase diagram of the real ZrO2–SiO2–Al2O3 system. Features of the iso- and polythermal sections of the phase diagram of the considered system, which were calculated using the thermodynamic NUCLEA database, were discussed in comparison with the sections of the obtained 3D-model. [ABSTRACT FROM AUTHOR]

Because of the many contradictions, connected with the literature data about the binary systems, which form the ternary LiF–KF–RbF system, three possible versions of the T–x–y diagram geometric structure of this system were proposed and their three-dimensional computer models had been designed. [ABSTRACT FROM AUTHOR]

The aim of this article is to predict possible invariant reactions in a quaternary system formed by oxides of titanium, aluminum, silicon, and zirconium. As a result, based on the data on invariant transformations in faceting ternary systems, a scheme of phase reactions with the participation of a liquid is derived, and then the contours of the liquidus hypersurfaces are described for basic invariant points belonging to binary and ternary systems, as well as the six obtained points of the quaternary system: two are peritectic, two are eutectic, and two are intermediate, corresponding to phase reactions of two variants of the peritectic type. [ABSTRACT FROM AUTHOR]

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In view of the contradictory opinions on the formation of zircon ZrSiO4 in the ZrO2–SiO2 system (by a peritectic or peritectoid reaction), two variants of prototypes of a three-dimensional (3D) computer model of the T–x–y diagram of the ZrO2–SiO2–Al2O3 system were constructed and used to consider in detail the possible invariant transformations in the subsolidus with the participation of the polymorphs of ZrO2 and SiO2. Because the later publication tended toward the formation of zircon by the peritectoid reaction, a 3D model of the corresponding T–x–y diagram of the real ZrO2–SiO2–Al2O3 system, which is constituted by 177 surfaces and 67 phase regions, was designed and can be used in practice. [ABSTRACT FROM AUTHOR]

Experimental study of phase equilibria in quaternary Fe-Ni-Co-Cu system has been carried out using differential thermal analysis, scanning electron microscopy and energy dispersive x-ray spectrometry. Experimental data obtained for several synthesized alloys in the Fe-Ni-Co-Cu system have been used for plotting the liquidus and solidus hypersurfaces projections also for design and verification of the T-x-y-z phase diagram. The 4D geometrical description of the Fe-Ni-Co-Cu system, plotted with applying fundamental geometrical principles of phase diagrams design, facilitates visualization of the liquidus and solidus hypersurfaces in 2D and 3D formats, and the entire four-dimensional T-x-y-z phase diagram using any 2D or 3D sections. [ABSTRACT FROM AUTHOR]

A computer model of the T-x-y diagram of MgO-SiO2-Al2O3 system is used to show the possibility of analysis of its microstructure constitution in terms of competition between primary and eutectic crystals by means of vertical mass balance diagrams calculated for a given centroid over the whole temperature range. The usefulness of horizontal mass balance diagrams is considered for studying phase relations at a fixed temperature along the chosen isopleth. Mass balances were used to determine the crystallization path at the quasi-peritectic liquidus point with the invariant reaction L + Al2O3 = 3Al2O3 · 2SiO2 + MgO · Al2O3, whose composition was taken into account in giving a rationale to corundum armor element technology. [ABSTRACT FROM AUTHOR]

A computer phase diagram model is constructed for the MgO-SiO2-Al2O3 system, giving its complete geometric description and containing 10 liquidus surfaces, a liquid-liquid phase separation surface, 75 ruled surfaces at the boundaries between two-phase and three-phase fields, 11 horizontal four-simplex at invariant temperatures, 21 two-phase fields, and 30 three-phase fields. The description of surfaces and three-phase fields is presented. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) computer models of Ag-Sb-Sn and MgO-Al2O3-SiO2 systems T-x-y diagrams have been designed. For the metal system two versions of 3D model of its phase diagram have been constructed according to the contradictions in the temperature intervals of the compound Sb2Sn3 stability. Possibilities of the analysis of the stages of crystallization and prediction of microstructural constituents with the aid of the calculation of vertical mass balance diagrams are demonstrated on the basis of the 3D computer model for the oxide system. [ABSTRACT FROM AUTHOR]