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Despite the importance of Al and Ta as alloying elements for Co- and Ni-base alloys, there has been limited research on the phase equilibria in the Al-Co-Ta and Al-Ni-Ta systems. Additionally, the available data are sparse and sometimes inconsistent due to the peculiar experimental challenges of these systems. Based on that, a comprehensive and critical evaluation of their phase equilibria is useful in view of further experimental and computational studies. Within this framework, the Al-Co-Ta and Al-Ni-Ta ternary systems and the respective binary subsystems are here critically assessed. All available literature investigations are analyzed and as a result, a set of self-consistent diagrams and tables are presented, reporting crystal structure data, liquidus projections, isothermal sections, etc. [ABSTRACT FROM AUTHOR]

During his time at Royal Institute of Technology (Kungliga Tekniska högskolan) in Sweden, the present author learned nonequilibrium thermodynamics from Mats Hillert. The key concepts are the separation of internal and external variables of a system and the definitions of potentials and molar quantities. In equilibrium thermodynamics derived by Gibbs, the internal variables are not independent and can be fully evaluated from given external variables. While irreversible thermodynamics led by Onsager focuses on internal variables though often mixed with external variables. Hillert integrated them together by first emphasizing their differences and then examining their connections. His philosophy was reflected by the title of his book "Phase Equilibria, Phase Diagrams and Phase Transformations" that puts equilibrium, nonequilibrium, and internal processes on equal footing. In the present paper honoring Hillert, the present author reflects his experiences with Hillert and his work in last 40 years and expresses his gratitude for all the wisdom and support from him in terms of "Hillert nonequilibrium thermodynamics" and discusses some recent topics that the present author has been working on. [ABSTRACT FROM AUTHOR]

A thermodynamic description of the intermetallic phases in the Fe-Cr-Mo-Ni system is presented based on previously unpublished experimental data in the Cr-Mo-Ni system. A review of experimental information from literature together with the new data provides a reliable base for the assessment. Together with previously published alloy systems, an open database for the Fe-Cr-Mo-Ni-N system is provided. Reliable calculations of the stability of the σ phase in the quaternary Fe-Cr-Mo-Ni system are shown, in support for predicted phase equilibria in super-duplex stainless steel. [ABSTRACT FROM AUTHOR]

Thermodynamic databases are indispensable in providing phase equilibria and phase transformation for new alloys design and process optimization. The quality of calculated results is strongly dependent on the accuracy of the thermodynamic database. A thermodynamic database for multicomponent copper alloys has been developed, which contains 30 elements covering the major and minor alloying elements of most commercial copper alloys. About 330 binary and 60 ternary systems have been assessed over the entire composition range. Examples of assessments and calculations for typical binary and ternary systems were presented. A wide range of compositions from pure copper to complex commercial copper alloys can be calculated. Scheil solidification simulations were carried out using the thermodynamic database for predicting the phase formation sequence during solidification, as well as phase compositions and phase fractions. In conjunction with a compatible kinetic database, the present established thermodynamic database was used to simulate the microstructure evolution of copper alloys during the ageing process. The simulated results were verified by key experiments, which proves the accuracy of the thermodynamic database established by us. [ABSTRACT FROM AUTHOR]

The method of constrained equilibria has already found extensive use for a good number of years in conjunction with the programmers library ChemApp and freely adaptable ASCII based thermodynamic datafiles. In the present paper a method is demonstrated which permits the application of this method in the framework of the Integrated Thermodynamic Databank System (ITDS) FactSage. Both, modules which interact with the databases and modules which carry out thermodynamic calculations are used, thus emphasizing the aspect of integration in the ITDS. In the paper a link will be established between original thoughts by J.W. Gibbs concerning the definition of the components of a system and kinetic inhibitions in the system and the method of constrained equilibria as such. Furthermore, reference is made to Mats Hillerts use of driving forces in complex (non-)equilibrium cases. A number of application cases with different degrees of complexity will be demonstrated. These range from partially or fully constrained complex equilibrium calculations to phase diagrams with new types of axis variables. [ABSTRACT FROM AUTHOR]

The liquidus surface, melting diagram (superposition of the liquidus and solidus surfaces) and Scheil diagram of the Hf-Rh-Ir system are presented for the first time based on results of the study of as-cast alloys using optical microscopy, scanning electron microscopy, electron probe microanalysis, differential thermal analysis and x-ray diffraction techniques taking into account the constitution of the solidus surface. In the Hf-Rh-Ir system a continuous series of solid solutions between isostructural compounds Hf2Rh and Hf2Ir (with the Ti2Ni-type structure), high-temperature modifications of compounds HfRh and HfIr (CsCl-type), HfRh3 and HfIr3 (AuCu3-type), iridium and rhodium (Cu-type), as well as solid solutions based on βHf, compounds Hf5Ir3 and Hf3Rh5 take part in phase equilibria. Two invariant four-phase reactions (peritectic at 1958 °C and transition at 1655 °C) involving liquid and corresponding three-phase equilibria take place in this system. [ABSTRACT FROM AUTHOR]

The phase diagram of the CaO-SiO2-Nb2O5-Fe2O3-TiO2 slag system has important significance for guiding the recycling and utilization processes of metallurgical slags containing niobium and titanium. In this paper, high-temperature equilibrium experiments were conducted at 1100 °C in air atmosphere to investigate the phase equilibria of the CaO-SiO2-Nb2O5-Fe2O3-TiO2 slag system. According to the experimental results, the liquidus surfaces of the liquid + CaTiO3 and liquid + SiO2 equilibrium coexistence regions in the CaO-SiO2-Nb2O5-5wt.% Fe2O3-TiO2 system at 1100 °C in air atmosphere were determined using interpolation and function fitting methods. Finally, the 1100 °C isothermal phase diagrams of the CaO-SiO2-Nb2O5-5 wt.% Fe2O3-TiO2 system were plotted. The composition range of liquid phase region was determined, and the positional relationships of the seven other equilibrium coexistence regions were illustrated. [ABSTRACT FROM AUTHOR]

The phase equilibria of the La-Co-Zr ternary system at 873 K and 1073 K were studied for the first time using equilibrated alloys employing scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) and x-ray diffraction (XRD). The crystal structures of the formed phases in La-Co-Zr alloys annealed at 873 K and 1073 K were identified through Rietveld refinement of the XRD results. The SEM-EDS and XRD results reveal that no ternary intermetallic compounds were detected in the La-Co-Zr ternary system and the binary intermetallic compound La5Co19 was not observed in the La-Co binary system. The solid solubility of the third element in the binary La-Co and Co-Zr intermetallic compounds was measured by EDS composition measurements. It was found that the maximum solid solubility of Zr in LaCo5 and LaCo13 is 1.8 and 4.0 at.% at 1073 K and it is 2.3 and 4.7 at.% at 873 K, respectively, while the maximum solid solubility of La in Co23Zr6 and Co2Zr is 1.3 and 1.6 at.% at 873 K and it is 3.8 and 6.1 at 1073 K. Furthermore, the solid solubility of Zr and La in the other La-Co and Co-Zr intermetallic compounds is negligible. Finally, the La-Co-Zr ternary isothermal sections at 873 K and 1073 K were established. [ABSTRACT FROM AUTHOR]

In this work, the phase equilibria of the binary Ag-In system were determined using electron probe microanalysis and differential scanning calorimetry on equilibrated alloys and diffusion couples. The compositions of the phase boundaries of solid phases that are highly scattered in the literature have been precisely determined. The temperatures of the invariant reaction ζ ⇄ γ + L and the polymorphic transformation ζ ⇄ γ are substantially lower than previously reported values. In addition, it was found that the In-rich ζ phase phase-separates after months of room-temperature aging. [ABSTRACT FROM AUTHOR]

The phase equilibria of the Er-Al-Zr ternary system at 500 °C were investigated using a combination of electron probe microanalyzer and x-ray diffraction. The microstructure and diffraction peaks were analyzed to determine the phases and compositions of Er-Al-Zr ternary system. Based on the experimental results, the isothermal phase diagram of the Er-Al-Zr ternary system consists of 14 three-phase equilibrium regions, 15 two-phase equilibrium regions, and 13 stable binary compounds, but no ternary compounds were detected. The solubility of Er in the Al2Zr, Al3Zr2, AlZr, Al3Zr4, Al2Zr3 is 9.9, 5.3, 9.0, 12.4, 6.7 at.%, respectively. The present work could be important for alloy design of Al-based alloys and thermodynamic analysis of the Er-Al-Zr ternary system. [ABSTRACT FROM AUTHOR]

Interactions of Ag and Sb(III) and Sn(IV) sulfides were investigated by x-ray diffraction, differential thermal analysis and microstructure analysis methods. The quaternary compound Ag11Sb3SnS12 was found for the first time in the Ag2S-Sb2S3-SnS2 system at 500 K (227 °C) at the intersection of AgSbS2-Ag8SnS6 and Ag3SbS3-Ag2SnS3. The compound melts congruently at 920 K (647 °C) and has a polymorphous transition at 646 K (373 °C). The quasi-ternary system is characterized by solid solution ranges of the binary compounds Ag2S, Sb2S3, SnS2, ternary Ag3SbS3, AgSbS2, Ag8SnS6, Ag2SnS3 and quaternary compound Ag11Sb3SnS12. The separation of the composition triangle into 10 single-phase, 18 two-phase, and 9 three-phase fields was established. Seven vertical sections were investigated of which five are quasi-binary (Ag3SbS3-Ag8SnS6, Ag3SbS3-Ag2SnS3, AgSbS2-Ag8SnS6, AgSbS2-Ag2SnS3, AgSbS2-SnS2). The AgSbS2-Ag4Sn3S8 and AgSbS2-Sb2SnS5 sections are non-quasi-binary due to peritectic formation of Ag4Sn3S8 and Sb2SnS5. The liquidus surface projection of the Ag2S-Sb2S3-SnS2 system consists of 10 fields of primary crystallization of the solid solutions α-Ag2S, β-Sb2S3, γ-SnS2, δ-Ag3SbS3, ε′-AgSbS2, ζ-Ag8SnS6, η-Ag2SnS3, σ-Ag11Sb3SnS12 and compounds Ag4Sn3S8 and Sb2SnS5. These are separated by curves of monovariant equilibria that converge at 9 ternary invariant points (7 eutectic (E1-E7) and 2 quasi-peritectic (U1, U2)). [ABSTRACT FROM AUTHOR]

Ternary alloys samples with 22, 25 and 23 different compositions were prepared for determining isothermal sections at 1123, 1223 and 1373 K, respectively. The microstructures, phase constituents and phase compositions of the annealed Cu-Nb-Ni alloys were analyzed by scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) and x-ray diffraction (XRD) methods. Two three-phase regions, fcc + NbNi 3 + Nb 7 Ni 6 , fcc + bcc(Nb) + Nb7Ni6, and three two-phase regions, fcc + NbNi 3 , Nb 7 Ni 6 + NbNi 3 , fcc + Nb7Ni6, are determined for isothermal sections at 1123 and 1223 K. Two three-phase regions, liquid + NbNi 3 + Nb 7 Ni 6 , liquid + bcc(Nb) + Nb7Ni6, and three two-phase regions, fcc + NbNi 3 , Nb 7 Ni 6 + NbNi 3 , liquid + Nb7Ni6, are determined for isothermal sections at 1373 K. The solubilities of Cu in NbNi3 and Nb7Ni6 were determined to be ~ 9.6 at.% and ~ 11.4 at.% at 1123 K, ~ 10.8 at.% and ~ 12.4 at.% at 1223 K and ~ 11.2 at.% and ~ 12.8 at.% at 1373 K, respectively. No ternary compounds were found. Based on the experimental phase equilibria data from the literature and the present work, a thermodynamic description of the Cu-Nb-Ni system was carried out by CALPHAD method. The substitutional solution model and sublattice model were employed to describe the solution phases and intermediate phases, respectively. A set of self-consistent thermodynamic parameters of the Cu-Nb-Ni system was conclusively obtained. Most of the reliable experimental data were reproduced by the present thermodynamic modeling. [ABSTRACT FROM AUTHOR]

The Sm–Ni–Al phase relationships at 800 °C have been investigated by using several well–focused experimental techniques such as X–Ray Powder Diffraction (XRPD), Light Optical Microscopy (LOM) and Scanning Electron Microscopy (SEM) coupled with Energy Dispersive Microprobe Analysis (EPMA). The isothermal section of the Sm–Ni–Al system at 800 °C was constructed according to the present experimental results. More than 50 alloys have been synthesized and characterized in the 30–100 at.% Al region. At 800 °C, 9 intermetallic phases have been confirmed, characterized and their relationships have been established. In the Al-rich corner, the presence of two ternary invariant reactions have been postulated whilst along the 16.67 at.% Sm isopleth, the presence of two structurally related extended solid solutions have been observed. The determined phase equilibria at 800 °C are discussed and compared with the isothermal section at 500 °C already reported in literature. [ABSTRACT FROM AUTHOR]

Phases and equilibria involved in the isothermal section at 500 °C of the ternary Al-Fe-Pr system have been here investigated in the whole composition range by means of X-ray diffraction, optical and scanning electron microscopy, and electron probe microanalysis. Phase equilibria are characterised by the formation of two binary solid solutions, Pr2(FexAl1−x)17 with 0.34 ≤ x ≤ 1.00 (hR57–Th2Zn17) and Pr(FexAl1−x)2 with 0 ≤ x ≤ 0.20 (cF24–Cu2Mg), and four ternary compounds, τ1-PrFe2Al10 (oS52-YbFe2Al10), τ2-PrFe2Al8 (oP44-CeFe2Al8), τ3-Pr(FexAl1−x)12 with 0.28 ≤ x ≤ 0.44 (tI26-ThMn12) and τ4-Pr6(FexAl1−x)14 with 0.63 ≤ x ≤ 0.81 (tI80-La6Co11Ga3), which have been confirmed. The solid solubility ranges of the binary and ternary compounds have been considered and trends of their lattice parameters studied. The complete isothermal section has been obtained and the general features of the section are discussed and compared with those of other ternary systems of light R (La, Ce, Pr, Nd, Sm) with Al and Fe. [ABSTRACT FROM AUTHOR]

Here, a complete phase equilibria picture in the Cu-As-S system was obtained by experimental study of carefully crystallized via long-term thermal annealing alloys by means of methods of differential thermal analysis and powder x-ray diffraction, as well as using the available literature data. The projection of the liquidus surface, the isothermal section at 300 K, and some vertical sections of the phase diagram are presented and discussed. The fields of primary crystallization of phases, types, and coordinates of invariant and monovariant phase equilibria are determined. The presented phase diagram reflects four ternary compounds Cu3AsS4, Cu12As4S13, Cu6As4S9, and CuAsS, which are synthetic analogues of natural copper-arsenic sulfide minerals. Particular attention is paid to the Cu2S-As2S3 section. It is shown that this section, in contrast to the literature data, is not quasi-binary. The thermodynamic data for copper-arsenic sulfides, previously obtained by the authors by the electromotive force method with Cu4RbCl3I2 solid electrolyte, have also been revised. Experimental data on the partial thermodynamic functions of copper in some phase regions of the Cu-As-S system were processed taking into account the constructed new version of the solid-phase equilibria diagram and updated data on the standard thermodynamic functions of formation and standard entropies of the ternary compounds Cu3AsS4, Cu12As4S13, Cu6As4S9, and CuAsS were obtained. [ABSTRACT FROM AUTHOR]

Hydrides enable handling hydrogen at low pressure and near room temperature, offering higher volumetric densities than compressed or liquid hydrogen and enhancing safety. The CALPHAD method, rooted in the principles of thermodynamics, offers a systematic approach for predicting phase equilibria and thermodynamic properties in multicomponent materials. This comprehensive review paper aims to provide a detailed overview of the application of the CALPHAD method in the realm of metallic and complex hydrides. After an introduction to the fundamental thermodynamic aspects of hydrides, key elements of applying the CALPHAD method to model metal-hydrogen systems and complex hydrides are discussed. Subsequently, recent publications are reviewed, highlighting key findings and recent progresses in the field. Finally, the challenges that must be overcome to achieve further progress in this area are explored. [ABSTRACT FROM AUTHOR]

The Mg-Sm phase diagram has been experimentally studied by x-ray diffraction, scanning electron microscope equipped with energy dispersive spectrometer, and differential scanning calorimetry. Five binary compounds, Mg41Sm5, Mg5Sm, Mg3Sm, Mg2Sm and MgSm were confirmed to exist in the Mg-Sm system. In addition to Mg2Sm and MgSm, Mg3Sm was found to be a congruently melting phase. The Mg5Sm and Mg2Sm were found to be only stable at high temperatures and decompose above 400 °C in this work. A special effort was made to determine the extent of the solid solubility ranges of Mg3Sm, Mg2Sm, MgSm and, γ-Sm. The Mg-Sm binary system was modeled using the Calphad approach based on new experimental data of this work and all reliable experimental information from literature. A complete thermodynamic description of the Mg-Sm system is obtained and extensive comparisons between calculated and experimental data are presented, indicating that almost all available experimental and theoretical data are fitted satisfactorily. [ABSTRACT FROM AUTHOR]

The phase diagram of the Fe-Zn binary system was evaluated based on the CALPHAD method with reference to the latest experimental data. The solubility ranges of the intermetallic compound phases, Γ-Fe4Zn9, Γ1-Fe11Zn40, δ1k-FeZn7, δ1p- Fe13Zn126, and ζ-FeZn13 were modeled considering their structures consisting of Zn12 icosahedra with Fe at the center (Fe1Zn12 clusters) as well as glue-like Fe and Zn atoms, and the miscibility gap between the δ1k and δ1p phases was also taken into account in the present calculations. The solubility of Fe in the liquid and (ηZn) phases that was confirmed as dozens of times larger than the values reported in the earlier literature could be calculated by introducing Fe1Zn12 associates to these solution phases. Consequently, all phase equilibria were adequately reproduced by the thermodynamic models and parameters revised in the present study. [ABSTRACT FROM AUTHOR]

Phase equilibria in the Pd rich region of the Au-Cu-In-Pd quaternary at 500 °C and 800 °C are investigated by SEM, EDX and XRD techniques. Part of the isothermal tetrahedron was constructed accounting for published data for bounding ternaries obtained earlier by the present authors. No quaternary phases were detected. The solubility of copper in the τ1 phase of the Au-In-Pd ternary (AuCu3 structural type) does not exceed 5 at.%. Gold solubility in the InPd2Cu phase of the Cu-In-Pd ternary is not less than 18 at.% at 500 °C, and at least 15 at.% at 800 °C. Analytical description of the boundaries of the FCC solid solutions in the equilibrium with the InPd3, InPd2Cu and ternary τ1 phase was performed for bounding Cu-In-Pd and Au-In-Pd ternaries as well as for the quaternary. The tie-lines of the equilibria, i.e. the compositions of the two phases in equilibrium, were described as a single entity. To this end, the approach used in the literature for regression analysis of phase compositions of the (γ + γ′) Ni based superalloys was modified. The parametric descriptions of the two-phase tie-lines' centers and those of the distribution coefficients of the components between the phases were built. The choice of parametrization is discussed. In particular cases of the ternaries and quaternary studied using the content of one or two of the components as parameters proved to be quite satisfactory. Very good description of the solubility lines and solubility surface including rather fine details has been achieved.Please check and confirm the edit made in the article title.Ok [ABSTRACT FROM AUTHOR]

This article considers the features and fundamental difficulties of studying low-temperature phase equilibria associated with an exponential increase in the required duration of syntheses with a decrease in temperature. Methods for accelerating the achievement of equilibrium, including the use of salt solvents, are also considered. The results of phase equilibria studies in the SrF2–LaF3 system using sodium nitrate and in the ZrO2–Sc2O3 system using sodium sulfate as fluxes are presented. The methods of extrapolation of phase diagrams to absolute zero temperature in accordance with the third law of thermodynamics are considered. Phase diagrams of the Au–Cu, Cu–Pd, Ni–Pt, and ZrO2–Y2O3 systems are presented. Phase equilibria with plagioclase ordering are considered separately, and the phase diagram of the albite–anorthite (NaAlSi3O8–CaAl2Si2O8) system is presented. As the temperature approaches absolute zero, the homogeneity region of labradorite shrinks to the compound NaCaAl3Si5O16. [ABSTRACT FROM AUTHOR]

In this paper, the NaBr-RbBr binary system was computationally investigated. Experimental data including phase diagram and thermodynamic information are used as input data for the CALPHAD assessment. The liquid and solid solutions are treated as substitutional solutions and the solid solutions (NaBr, RbBr, both FCC type) were modeled as a single phase with a miscibility gap. Our calculations are in good agreement with the phase diagram data and experimental thermodynamic data available in the literature. [ABSTRACT FROM AUTHOR]

Heavy p-elements-rare earth element tellurides are important multifunctional materials with thermoelectric, magnetic, optical, topological insulating, and other properties. This paper presents the results of a study of phase equilibria in the Tl2Te-TlBiTe2-TlGdTe2 system and the magnetic properties of the TlBi1−xGdxTe2 solid solutions. A diagram of solid-phase equilibria of the indicated system has been constructed. According to the data obtained, it is characterized by the formation of wide areas of homogeneity based on the initial compounds of the TlBiTe2-TlGdTe2 boundary system and a continuous series of solid solutions along the Tl9BiTe6-Tl9GdTe6 section (δ-phase). It has been shown that the homogeneity regions of the TlBiTe2 (β1) and TlGdTe2 (β2) compounds form a narrow (1-2 mol.%) band extending to 35 and 10 mol.% TlGdTe2 and TlBiTe2, respectively, along the boundary TlBiTe2-TlGdTe2 system while the homogeneity area of the δ-phase significantly extends into the compositions region rich in Tl2Te. Based on powder diffraction patterns, the phase compositions of the alloys and the crystallographic parameters of the identified solid solutions were determined. The work also presents several polythermal sections, isothermal sections at 760 and 800 K of the phase diagram, as well as a projection of the liquidus and solidus surface of the Tl2Te-Tl9BiTe6-Tl9GdTe6 subsystem. Magnetic properties of TlBi1−xGdxTe2 samples were investigated by magnetization and Electron Paramagnetic Resonance (EPR) measurements. It was found that these samples behave as a Curie-Weiss paramagnet containing Gd3+ ions with no indications of magnetic ordering or freezing down to 2 K. [ABSTRACT FROM AUTHOR]

The paper analyzes the works of the last decade on the study of ionic conductivity, thermoelectric, photovoltaic, photocatalytic, optical, etc. properties of the argyrodite family compounds (prototype Ag8GeS6), as well as phases and composite materials based on them. Considered works allow us to characterize them as valuable environmentally friendly functional materials with great potential for practical application. The main approaches which have been used in these works to enhance functional properties, as well as to improve the application capabilities of this class of substances have been analyzed. The importance of further systematic investigations on their design based on the "composition-structure-property" relationship has been noted. In the present review, special attention is paid to the analysis of works on phase equilibria in the corresponding systems since the information accumulated in phase diagrams is extremely important for optimizing the properties of compounds through targeted variation of composition and structure. Available data on the phase equilibria and thermodynamic properties of ternary and quaternary systems forming Cu/Ag argyrodite compounds and solid solutions based on them are presented and analyzed. It has been shown that anionic and Cu ↔ Ag substitutions in compounds lead to a strong decrease in their polymorphic phase transition temperatures and an expansion of the temperature-composition ranges of the existence of high-temperature ion-conducting phases up to room temperature and below. The possibility of replacing part of the chalcogen atoms in the compounds with halogens, and the Cu(Ag) atoms with elements of the zinc subgroup, which expands the range of argyrodite phases is also shown. The significance of expanding studies of phase equilibria and thermodynamic properties of these systems, especially five-component and more complex systems possessing a big possibility of the formation of high-entropy argyrodite phases, which have thermodynamic stability in a wide temperature-composition range and better applied characteristics has also been specified. [ABSTRACT FROM AUTHOR]

Systematic studies on the lattice expansion and order-disorder phase equilibria are attempted for the A-B binary alloy on the two-dimensional square lattice. The atomic pair potentials are described by the Morse potential and the configurational entropy is formulated within the pair approximation of the Cluster Variation Method (CVM). The lattice expansion of the uniformly deformable lattice is enhanced by introducing lattice vibration effects through the Debye–Grüneisen model. The introduction of the local lattice distortion by continuous displacement CVM (CDCVM) further increases the lattice expansion. The transition temperature obtained for a uniformly deformable lattice is reduced by the thermal vibration effects, which is interpreted as the curvature effects of atomic pair potentials. The local lattice relaxation further reduced the transition temperature, which is ascribed to the additional freedom of distributing atomic pairs over a wide range of distances. [ABSTRACT FROM AUTHOR]

During powder-pack boronizing, an alloy is enveloped by a mixture comprising a source of boron, a diluent and an activator. If the activity of B in boriding media exceeds that in alloys, then this difference is a driving force, which, at elevated temperatures, may result in single- or multi-layered protective coatings. If it is intended to model and optimize this diffusion-controlled process, then an ability to calculate and control boron activity in both currently employed and prospective diluent-source-activator blends would be indispensable. In literature, such calculations are seldom performed, which likely reflects a reluctance or trepidation to deal with systems routinely containing five or more components. Consequently, it is commonly yet mistakenly believed that the activity of B can be smoothly changed by gradually changing a fraction of its source. In reality, a multiphase nature of boronizing powders is manifested in intricate concentration dependencies of boron activity with intervals where it remains constant. Another puzzling feature is the constancy of boron activity in phase fields which ostensibly have a non-zero number of degrees of freedom. In this work, a seeming inconformity with Gibbs' phase rule is addressed. Although it is not unreasonable to expect that an equilibrium phase assemblage at high temperatures would differ from ingredients mixed at room temperature, it is instructive to realize how drastically dissimilar they can be in some cases. If a boriding medium is utilized several times (a routine industrial practice), then its evolution caused by multiple heating and cooling cycles should not be overlooked. [ABSTRACT FROM AUTHOR]

There is an increasing demand for materials capable of withstanding ever-higher temperatures. However, because the difficulties associated with carrying out experimental investigations at very high temperatures are significant, the published information relating to the phase stability of potential refractory materials is, in many instances, still lacking. The work described in this paper attempts to rectify this deficit through the on-going development of a thermodynamic database for high-temperature materials based on carbides, nitrides, borides, and silicides. Because of technological requirements of high-temperature stability and strength, combined with lightness, these are the materials that come into question most frequently for high-temperature applications. In developing the present database, and to ensure reliability of its use, emphasis has been placed on the need to maintain the compatibility of data and modeling when assessing experimental data and estimating missing values. The methods used to achieve compatibility of published information are described and calculations of phase equilibria relevant to the industrial application of various refractory materials are presented. The similarity to, and the importance of the scientific background and published work of Ted Massalski for the work of the present author is stressed. [ABSTRACT FROM AUTHOR]

Phase equilibria were investigated between 200 and 800 °C in the Cu-Zn binary system. Wavelength dispersive spectroscopy (WDS) was performed to determine the equilibrium compositions, and differential scanning calorimetry (DSC) was performed to investigate the solidus and liquidus temperatures and the invariant reaction temperatures of the Zn-rich portion. The β/(α + β) boundary in the Cu-rich portion extended toward the Cu-rich side as the temperature decreased below the A2–B2 order–disorder transformation temperature, and the phase boundaries of the γ, δ and ε phases shifted toward the Cu-rich side. The liquidus temperatures of the ε + liquid were higher than those of the previous report. From the experimental results, the phase diagram of the Cu-Zn binary system was determined in the whole composition range. [ABSTRACT FROM AUTHOR]

Interactions of Ag and Sb(III) and Sn(IV) sulfides were investigated by x-ray diffraction, differential thermal analysis and microstructure analysis methods. The quaternary compound Ag11Sb3SnS12 was found for the first time in the Ag2S-Sb2S3-SnS2 system at 500 K (227 °C) at the intersection of AgSbS2-Ag8SnS6 and Ag3SbS3-Ag2SnS3. The compound melts congruently at 920 K (647 °C) and has a polymorphous transition at 646 K (373 °C). The quasi-ternary system is characterized by solid solution ranges of the binary compounds Ag2S, Sb2S3, SnS2, ternary Ag3SbS3, AgSbS2, Ag8SnS6, Ag2SnS3 and quaternary compound Ag11Sb3SnS12. The separation of the composition triangle into 10 single-phase, 18 two-phase, and 9 three-phase fields was established. Seven vertical sections were investigated of which five are quasi-binary (Ag3SbS3-Ag8SnS6, Ag3SbS3-Ag2SnS3, AgSbS2-Ag8SnS6, AgSbS2-Ag2SnS3, AgSbS2-SnS2). The AgSbS2-Ag4Sn3S8 and AgSbS2-Sb2SnS5 sections are non-quasi-binary due to peritectic formation of Ag4Sn3S8 and Sb2SnS5. The liquidus surface projection of the Ag2S-Sb2S3-SnS2 system consists of 10 fields of primary crystallization of the solid solutions α-Ag2S, β-Sb2S3, γ-SnS2, δ-Ag3SbS3, ε′-AgSbS2, ζ-Ag8SnS6, η-Ag2SnS3, σ-Ag11Sb3SnS12 and compounds Ag4Sn3S8 and Sb2SnS5. These are separated by curves of monovariant equilibria that converge at 9 ternary invariant points (7 eutectic (E1-E7) and 2 quasi-peritectic (U1, U2)). [ABSTRACT FROM AUTHOR]

Phase equilibria of the Ti-Ga-Sn system have been determined at primary crystallization and at 1000 °C in the composition interval ~ 50-100 at.% Ti based on differential thermal analysis, x-ray powder diffraction, scanning electron microscopy and electron microprobe analysis. Partial liquidus and solidus projections, the melting diagram, a number of vertical sections, isothermal section at 1000 °C, as well as the reaction scheme (Scheil diagram) for the Ti-Ga-Sn system were constructed. A ternary compound Ti5GaSn2 (τ) (Nb5SiSn2-type structure, tI32-I4/mcm), found by us previously, forms by peritectic reaction L + Ti2(Sn, Ga) + Ti5(Sn, Ga)3-4 ⇄ τ at 1500 °C and has a wide homogeneity range from 9 to 23.5 at.% Ga at solidus temperature and from 4 to 34 at.% Ga at 1000 °C, and located along constant composition of ~ 62.5 at.% Ti. D88-type compounds Ti5Sn3 and Ti5Ga4 form a continuous solid solution, denoted Ti5(Sn, Ga)3-4, at all investigated temperatures. Ga-poor part of it (below ~ 12.5 at.% Ga) forms by an interstitial mechanism, while in the interval above ~ 12.5 at.% Ga it is a substitutional phase. Isostructural compounds Ti2Sn and Ti2Ga also form a continuous solid solution Ti2(Sn, Ga) at solidus temperatures, which decomposes with decreasing temperature. Meanwhile, at 1000 °C, one more continuous solid solution Ti3(Sn, Ga) forms between isostructural compounds Ti3Sn and Ti3Ga. [ABSTRACT FROM AUTHOR]

The phase equilibria in the Al-Ta-V ternary system at 1000 °C and 1200 °C have been studied by using electron probe microanalysis and x-ray diffraction. τ-Al2.9Ta2.7V1.4 phase was found in the Al-Ta-V ternary system in both isothermal sections. The addition of V stabilizes the Al69Ta39 phase at 1000 °C. The line compound Al3(V,Ta) (D022-type) forms a continuous phase region from the Al-V side to the Al-Ta side at the two temperatures. Based on our experimental results, reported liquidus projection of the ternary Al-Ta-V system and thermodynamic data of the binary systems of Al-V, Al-Ta and V-Ta, a thermodynamic evaluation of Al-Ta-V system was carried out by CALPHAD method. A set of reliable thermodynamic parameters for the Al-Ta-V system was obtained. The current calculation results agree well with the available experimental data. The invariant reaction scheme of Al-Ta-V ternary system was presented. The present study could provide essential experimental and thermodynamic data for establishing a comprehensive Co-based superalloy database. [ABSTRACT FROM AUTHOR]

This article is a special issue of the Journal of Phase Equilibria and Diffusion dedicated to honoring the late Professor Thaddeus B. "Ted" Massalski, who passed away in December 2022 at the age of 96. Professor Massalski made significant contributions to the field of materials science, particularly in alloy phase stability, phase transformations, phase diagrams, and thermodynamics. He also received numerous awards and honors throughout his career. This special issue includes a variety of articles that showcase the broad impact of Professor Massalski's research in the field of materials science. [Extracted from the article]

The quasi-ternary system Cu2Se-In2Se3-CuI has been investigated by x-ray diffraction and differential thermal analysis. The isothermal section at 770 K and the liquidus surface projection of the system have been built. For the first time, the primary crystallization regions, and the coordinates of the invariant and monovariant equilibria have been determined. In the system, the regions of the solid solutions based on the binary, ternary, and quaternary compounds have been investigated. The formation of the CuIn2Se3I quaternary compound, which melts congruently at 1213 K and has a homogeneity region of 15 and 9 mol.% CuI within the composition triangle has been established. For the first time, the crystal structures of CuGa2Te3I and AgGa2Te3Br compounds have been studied using a powder method. They crystallize in the tetragonal symmetry, Space Group I-4, a = 5.9147(4) Å, c = 11.952(2) Å for CuGa2Te3I; a = 6.2977(3) Å, c = 11.9473(7) Å for AgGa2Te3Br compound, respectively. The connection of their structures with the structures of the defective diamond-like semiconductors has been discussed. [ABSTRACT FROM AUTHOR]

Recent design and development of precipitate reinforced refractory metal alloys demonstrate the possibility of A2 + B2 bcc superalloys as a new class of high temperature materials. Existing β-Ti alloys do not typically employ reinforcement with intermetallics, as in other high temperature alloys; to this effect sufficient additions of Fe, a low cost β-Ti stabiliser, can promote formation of an ordered-bcc intermetallic phase, β′-TiFe (B2), offering scope to develop a β + β′ dual-phase field. However, key uncertainties exist in the base Ti-Fe binary. The current research evaluates the formation of ordered-bcc TiFe precipitates within a disordered-bcc β-Ti matrix through variable heat treatment strategies. The microstructure optimisation has revealed new insight into the Ti-Fe phase equilibria at near eutectoid temperatures in the purported dual-phase field, where a complex interplay between β-Ti, β′-TiFe and α-Ti exists. [ABSTRACT FROM AUTHOR]

Phase equilibria in Ga-Sn-Te system plays a key role in designing multiphase thermoelectric materials. SnTe is a promising alternative to the well-known PbTe (toxic) thermoelectric phase in the Ga-Sn-Te system. In the present study, various compositions have been selected using the thermodynamically developed database of the Ga-Sn-Te system to understand the phase equilibria and microstructural features. The alloys with multiphase combinations of SnTe, Ga6SnTe10, GaTe, and Te were produced using vacuum induction melting. In addition, the developed microstructures were characterized using x-ray diffraction, optical and Scanning Electron Microscopy techniques. The microstructures reveal interesting eutectic morphologies of Ga6SnTe10/Te, Ga6SnTe10/SnTe, and GaTe/SnTe. The microstructural features were explained using Scheil-Gulliver cooling calculations. Moreover, the thermal analysis of the investigated alloys was also performed to validate the thermodynamically predicted liquidus temperatures and various phase transitions in the investigated alloys. [ABSTRACT FROM AUTHOR]

In this study, the phase equilibria of the Nb-V-Hf ternary system at 1300, 1100 and 1000 °C were experimentally investigated by means of back-scattered electron imaging, electron probe microanalysis, and x-ray diffraction. The results show that one ternary Laves compound with a hexagonal C14 structure is found in the isothermal sections that were studied. The bcc phase forms a large continuous solid solution, and no phase separation occurs at 1000 °C as had been claimed in the literature. As the temperature rises from 1000 to 1300 °C, the bcc structure can be observed in the Hf-V side, and the phase region of C15 reduces. [ABSTRACT FROM AUTHOR]

The equilibrium phase relations of the Nd2O3-CaO-Fe2O3 system were investigated at 1473 K in air using a high-temperature isothermal equilibration technique followed by quenching. Using x-ray diffraction (XRD) and scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS) analysis of quenched samples, twelve two-phase equilibria regions and eleven three-phase equilibria regions were observed. A series of solid solutions Nd1−xCaxFeO3−δ formed in the ranges of 0 ≤ x ≤ 0.2, 0.5 ≤ x ≤ 0.6, and 0.6 < x ≤ 1 were found. Ternary compound Ca1−xNd1+xFeO4−δ was observed to be stable at 1473 K with limited substitution of Nd by Ca. The 1473 K isothermal section was constructed for the Nd2O3-CaO-Fe2O3 system. [ABSTRACT FROM AUTHOR]

The LiCl-KCl-GdCl3 quasi-ternary phase diagram has been investigated by differential thermal analysis (DTA) and x-ray diffraction (XRD) techniques. These experiments showed that the LiCl-KCl-GdCl3 system consists of several pseudo-ternary and quasi-ternary composition triangles. Coexisting phases in the solid state at 260 °C were characterised by XRD analysis of the equilibrated samples. Quasi-ternary compounds were not found. The ternary eutectic temperature was observed at 315 ± 2 °C and its composition was delineated at 57 mol.% LiCl-42 mol.% KCl-1 mol.% GdCl3 in the LiCl-KCl-K3GdCl6 composition triangle. The other ternary eutectic temperature was observed at 308 ± 2 °C in the LiCl-K3GdCl6-K2GdCl5 composition triangle. Its composition was deduced at 40.2 mol.% LiCl-41.7 mol.% KCl18.1 mol.% GdCl3. Another ternary eutectic temperature was observed at 360 ± 9 °C in the LiCl-K2GdCl5-KGd2Cl7 composition triangle. Its composition was deduced at 33.8 mol.% LiCl-29.5 mol.% KCl-36.7 mol.% GdCl3. The fourth ternary eutectic temperature was observed at 362 ± 4 °C in the LiCl-KGd2Cl7-LiGdCl4 composition triangle. Its composition was delineated at 48 mol.% LiCl-11 mol.% KCl-41 mol.% GdCl3. The ternary pseudo-peritectic reaction "L+GdCl3 ↔ LiGdCl4+KGd2Cl7" was observed at 370 ± 3 °C. Its composition was delineated at 46.7 mol.% LiCl-10.5 mol.% KCl-42.8 mol.% GdCl3. The primary and secondary crystallisation temperatures, as well as polymorphic phase transformation temperatures of the samples were deduced from the heating runs of DTA experiments. Further, phases responsible for the various thermal events were ascertained. Isothermal composition triangles at selected temperatures, Scheil diagram and the polythermal liquidus projection with isothermal contours of the ternary phase field were drawn. [ABSTRACT FROM AUTHOR]

Phase equilibria in the Zr-Ti-Cu system have been studied by differential thermal analysis, scanning electron microscopy, x-ray microanalysis, and x-ray diffraction. Based on the obtained results, a ternary phase diagram was constructed over the entire composition range in the crystallization interval. The results are presented in the form of liquidus and solidus projections, the Scheil reaction scheme, and isopleths for sections of 40 and 70 at.% Cu. Phase equilibria in the system are defined by the ternary compound ZrTiCu2 (τ1) and the binary-based phase Zr14Cu51. These phases have the widest fields of primary crystallization on the liquidus projection and form two-phase equilibria with all other phases on the solidus projection. The solidus projection contains 11 three-phase fields. Two of them form by invariant four-phase reactions of the transition type, the rest by eutectic ones. A comparison of the solidus projection with the published isothermal sections at 800 and 750 °C led to the need for two solid-state four-phase invariant equilibria involving binary Ti-Cu intermetallic compounds. They are shown to occur between 840 and 850 °C. The ternary compound Zr22Ti14.5Cu63.5 (τ2) was shown to form in the solid state at 827 °C by three-phase invariant reaction τ1 + Zr14Cu51 ⇄ τ2. [ABSTRACT FROM AUTHOR]

The phase relationships of the Ni-Al-Cr-Y quaternary system can provide theoretical guidance for the design of MCrAlY (M = Ni and/or Co, Fe) overlay coatings on the surface of superalloys. The 900 °C isothermal section of the Ni-Al-Cr-Y quaternary system with Ni fixed at 55 at.% and the Ni-Al-Y ternary system were studied experimentally by using equilibrated alloys, with x-ray diffraction and scanning electron microscopy with energy dispersive spectroscopy. Thirty three-phase regions were confirmed, and six three-phase regions were determined in the isothermal section of the Y-poor side in Ni-Al-Y ternary system at 900 °C. Aluminium could replace Ni in the line compounds Ni5Y, Ni3Y and Ni2Y; similarly, Ni could replace Al in the line compounds Al2Y, AlY and Al2Y3. The experimental results showed that there are twelve ternary compounds stable at 900 °C, and the τ13-Ni6Al16Y3 phase and τ14-NiAl3Y2.25 phase are the new ternary compounds found in this work with composition ranges from about 23.5-24.9 at.% Ni, 63.1-64.8 at.% Al, 11.2-12.1 at.% Y and 16.3-17.0 at.% Ni, 47.2-48.2 at.% Al, 35.5-36.8 at.% Y, respectively. In the isothermal section of the Ni-Al-Cr-Y quaternary system at 900 °C with 55 at.% Ni, six four-phase regions were experimentally determined, and one four-phase region was inferred. The results indicated that (Cr) could equilibrate with all phases in the quaternary system. In the present work, no new quaternary compounds were found. [ABSTRACT FROM AUTHOR]

The aim this work was the reinvestigation of phase equilibria in Bi-Te system. The as-cast and long-time equilibrated alloys of Bi-Te binary system were analysed by scanning electron microscopy, X-ray diffraction (XRD) and differential thermal analysis (DTA) methods. The primary solidified phases were identified for as-cast samples. The existence of the four intermetallic phases: Bi2Te3, BiTe, Bi2Te, Bi7Te3 was confirmed. Three of them melt incongruently in peritectic reactions. The model parameters of all phases in this system were assessed by optimization using available data by Calphad method. The stabilisation of these phases in other ternary systems was discussed taking into consideration its future application in thermodynamic description of Ag-Bi-Te ternary system. [ABSTRACT FROM AUTHOR]

The phase equilibria of the Cu2S-SiS2-GeS2 system have been studied in the Cu2S-Cu8SiS6-Cu8GeS6 composition area. Based on data obtained from differential thermal analysis, powder x-ray diffraction, and SEM-EDS techniques, the T-x diagram of the Cu8SiS6-Cu8GeS6 boundary system and two internal polythermal sections, as well as the isothermal section at 300 K of the phase diagram and the liquidus surface of the Cu2S-Cu8SiS6-Cu8GeS6 system were constructed. The areas of primary crystallization and homogeneity of phases, the nature, and temperatures of invariant and monovariant equilibria were determined. Continuous solid solutions based on both crystalline modifications of the starting compounds of the Cu8SiS6-Cu8GeS6 boundary system, have been revealed, which are of interest as environmentally friendly functional materials. The temperatures and enthalpies of phase transitions of Cu8SiS6 and Cu8GeS6 compounds, and Cu8Si(1−X)GeXS6 solid solutions were determined using differential scanning calorimetry. The entropies of phase transitions for end-member compounds were also calculated. It is shown that the heats and entropies of phase transitions of these phases are anomalously large in comparison with the thermodynamic functions of ordinary polymorphic transitions. Apparently, this is due to a significant increase in the degree of disorder in the cationic sublattice upon transition to the high-temperature ion-conducting phase. It has also been established that the heats of phase transitions of solid solutions are practically equal to the sum of the corresponding functions of the end-member compounds. [ABSTRACT FROM AUTHOR]

Vaporisation studies were carried out over the solid region of LiCl(cr), KCl(cr) and liquid region of LiCl-KCl-UCl3 ternary salt system by using Knudsen Effusion Mass Spectrometry (KEMS) in the temperature range of 715–913 K. Monomeric and dimeric species were observed in the vapour phase in equilibrium with their respective salts, LiCl(cr) and KCl(cr). LiCl(g), Li2Cl2(g), KCl(g), K2Cl2(g), and UCl3(g) were the neutral species observed in the equilibrium vapour over ternary salt. Partial pressure–temperature relations for vapour species were derived using in-situ calibration from pressure dependent equilibrium constants as well as using pure silver as external calibrant. Using p-T relations, various heterogeneous reaction equilibria that exist between condensed phase-gas phase and the dissociation equilibra of following gas phase reactions: Li2Cl2(g) = 2LiCl(g); K2Cl2(g) = 2KCl(g) were evaluated by using 2nd and 3rd law methods. Also, the enthalpies of pressure-independent reactions: LiCl(cr) + LiCl(g) = Li2Cl2(g); KCl(cr) + KCl(g) = K2Cl2(g) were evaluated by using 3rd law method. Knudsen effusion mass spectrometric studies on LiCl-KCl-UCl3 ternary salt system were carried out for the first time. [ABSTRACT FROM AUTHOR]

Thermodynamic databases are essential to understanding alloy properties and guiding materials design. In this work, the mixing enthalpies of the liquid phase in the Gd-Te, Dy-Te and Ho-Te binary systems are calculated using Ab-initio Molecular Dynamics (AIMD) simulations and the thermodynamic parameters are determined using the CALculation of PHAse Diagrams (CALPHAD) method combined with the phase equilibrium data and thermodynamic data. The associated solution model is employed to describe the liquid phase of these systems. The sublattice model (Gd,Te)0.0296(Gd)0.4(Te)0.5714, (Dy,Te)0.0286(Dy)0.4286(Te)0.5714 and (Ho,Te)0.5(Te)0.5 are utilized to describe Gd2Te3, Dy2Te3 and HoTe, respectively. The line compounds, i.e. GdTe, DyTe, and DyTe2, are modeled using the stoichiometric model. The calculated results can describe the experimental and thermodynamic information reported in the literature. In addition, the existence of a liquid-liquid separation in the Dy-rich side in the Dy-Te binary system is proposed in this work. [ABSTRACT FROM AUTHOR]

Sb2Te3 is an important thermoelectric material. Co is a potential diffusion barrier. This study examined the electroplated Co/Sb2Te3 interfacial reactions at 300 °C, 400 °C and 500 °C. To provide fundamental information and for better understanding the reaction paths, the Co-Sb-Te phase equilibria isothermal sections at these three temperatures are proposed. No ternary compound is found. The 400 °C isothermal section contains (Co), (Sb), (Te), β-CoSb, β-Co1−xTe, CoSb3, δ-(Sb2Te), γ-(SbTe), Sb2Te3 and a continuous solid solution γ-Co(Sb,Te)2. At 500 °C, except for Te being molten, the phase relationships are similar to those at 400 °C. At 300 °C, although γ-CoSb2 and γ-CoTe2 have very significant mutual solubilities, they are two separate phases and do not form a continuous solid solution. In the Co/Sb2Te3 couple reacted at 300 °C, only one reaction phase, γ-CoTe2 with Sb solubility, is formed. Similar results are found in the Co/Sb2Te3 couple reacted 400 °C, and the reaction phase is the continuous solid solution γ-Co(Sb,Te)2. Two reaction phases, β-Co1-xTe and γ-Co(Sb,Te)2, are found in the couple reacted at 500 °C. The compositional ratio of Sb/Te in the reaction phase remained at 2/3 indicates that Co is the dominating diffusion species. The reaction phases are formed rapidly by Co penetration into the Sb2Te3 substrate. A peculiar phenomenon was found with the reaction layer that formed on the side of Co that was not in direct contact with the Sb2Te3 substrate which will be further investigated. [ABSTRACT FROM AUTHOR]

Phase equilibria in the Hf–Rh–Ir system at subsolidus temperatures (about 20-50 °C below solidus temperatures) were studied using optical microscopy, scanning electron microscopy, electron probe microanalysis, differential thermal analysis, x-ray diffraction and solidus temperature measurements (Pirani-Althertum technique). For the first time it was established that the solid solution based on βHf, continuous series of solid solutions between isostructural (Cu-type) components iridium and rhodium, isostructural compounds Hf2Rh and Hf2Ir (Ti2Ni-type), high-temperature modifications of HfRh and HfIr (CsCl-type), HfRh3 and HfIr3 (AuCu3-type), as well as solid solutions based on the compounds Hf5Ir3 and Hf3Rh5 take part in phase equilibria. Solidus surface of this system is formed by seven single-phase surfaces corresponding to solid solutions based on components and above-mentioned compounds, eight tie-line surfaces limiting the two-phase volumes, and two isothermal planes corresponding to invariant four-phase equilibria with participation of the liquid phase (at 1958 and 1655 °C). [ABSTRACT FROM AUTHOR]

The Journal of Phase Equilibria and Diffusion has announced Dr. Alexander Pisch as the new Associate Editor. Dr. Pisch, based in Grenoble, France, is a research director at the French National Centre for Scientific Research with expertise in novel, low CO2 building materials. His research focuses on phase equilibria and thermodynamic properties of cement-related compounds. Dr. Pisch joins a diverse group of current Associate Editors from various countries and institutions, contributing to the journal's global perspective on materials science and engineering. [Extracted from the article]

The phase equilibria of the Ce-Co-Zr ternary system at 873 and 1073 K were determined for the first time by using equilibrated alloys in combination with scanning electron microscopy with energy dispersive spectroscopy and x-ray diffraction. No stable ternary intermetallic compounds were detected in the Ce-Co-Zr ternary system. Due to the partial substitution of Ce by Zr, the metastable binary intermetallic compound CeCo7 with a solubility of 3.3 at.% Zr is stabilized at 873 K. The experimental results demonstrate that the maximum solubilities of Zr in the intermetallic compounds Ce2Co17, CeCo5, Ce5Co19, Ce2Co7, CeCo3, and CeCo2 at 873 K are 4.3, 2.6, 2.4, 9.0, 17.9, 3.5 at.%, respectively, while the maximum solubilities of Ce in the intermetallic compounds Co23Zr6, Co2Zr, and CoZr2 are 6.7, 1.7, and 2.3 at.%. Meanwhile, the maximum solubilities of Zr in Ce2Co17, CeCo5, Ce5Co19, Ce2Co7, CeCo3 and CeCo2 at 1073 K were measured to be 4.0, 7.5, 1.9, 6.8, 17.1, and 9.1 at.%, respectively, while the maximum solubilities of Ce in the intermetallic compounds Co23Zr6 and Co2Zr were determined to be 7.0 and 4.5 at.%, respectively. Finally, the isothermal sections of the Ce-Co-Zr ternary system at 873 and 1073 K were established in this work. [ABSTRACT FROM AUTHOR]

Thermodynamic optimization of the Ln-Ru (where Ln = Ce and Sm ) binary systems was carried out by means of CALPHAD method. Our approach is based on the critical review of the available experimental data published in literature, including both phase equilibria and thermodynamic data. Nine intermediate phases: Ln 3 Ru , Ce 7 Ru 3 , Ce 16 Ru 9 , Ce 4 Ru 3 , Sm 2 Ru 5 , Ru 25 Sm 44 , and LnRu 2 presented in both binary systems, were treated as stoichiometric compounds. The exponential and linear models were used to describe the temperature dependence of the excess quantities of liquid, (δ Ce) , (γ Ce) , (β Ce) , (α Sm) , (β Sm) , (γ Sm) and (Ru) solid solution phases. They were compared with the combined linear–exponential temperature dependence of the resulting interaction energies. The self-consistent thermodynamic parameters used to describe the Gibbs energies of various phases in the Ln-Ru binary systems were obtained through Thermo-Calc software. The obtained calculated results are in excellent agreement with available phase equilibrium and thermodynamic data. [ABSTRACT FROM AUTHOR]

A critical evaluation of all available phase diagram and thermodynamic data has been performed for Ag-As, Ag-S, As-S and Ag-As-S systems, including a detailed review of the gaseous species involved in the As-S system. Thermodynamic assessments over the whole composition range for these four systems are presented using the CALPHAD method. To predict thermodynamic properties and phase equilibria, the Modified Quasichemical Model for short range ordering was used for the liquid phases, and the Compound Energy Formalism was used for the solid solutions. For the As-S binary system, natural logarithm terms for the temperature dependence of the excess Gibbs energy of the liquid solution have been used. This led to a significant improvement compared with the previous assessment of this system. The optimization of Ag-As-S systems is in good agreement with the existing experimental data. [ABSTRACT FROM AUTHOR]

Data on the equilibrium solubilities of the α Al-Li solid solution phase and the ordered metastable δ′ Al3Li (L12 crystal structure) precipitate phase are critically reviewed, and a new binary alloy phase diagram is proposed. The δ′ solvus, describing the equilibrium solubility of Li in the α phase, Xαe, in atom fraction Li, is given by the equation X α e = 0.600 86 exp - 8669.55 / R T , where R is the gas constant, and the temperature T is in K. The α solvus, i.e. the equilibrium solubility of Li in the δ′ phase, Xδ′e, is given by the equation X δ ′ e = 0.1809 + 6.413 × 1 0 - 4 T - 1.861 × 1 0 - 6 T 2 + 1.4684 × 1 0 - 9 T 3 , which represents a compromise between previously published theoretical curves that predict retrograde behavior. It is emphasized that that all the data cited and re-analyzed exclusively involve binary Al-Li alloys. The new phase diagram eliminates data that were previously mis-attributed. Most importantly, it is informed by considerable re-analysis of previously published data, supplemented by the inclusion of data that were not previously considered, and eschews data on both Xαe and Xδ′e that are indubitably non-equilibrium in nature. [ABSTRACT FROM AUTHOR]