Section Of Phase Diagram Research Articles

Research on rigid-flexible coupling nonlinear dynamics of light commercial vehicle considering frame flexibility

Commercial vehicles play a vital role in the transportation industry. Generally, there will present a complex nonlinear dynamic behavior composed of periodic, quasi-periodic, and even chaotic vibration in vehicle vertical system under the continuous speed bump excitation. To explore the nonlinear dynamic behavior of vehicle system, a new rigid-flexible coupling nonlinear dynamic model for light commercial vehicle has been developed theoretically with considering the frame flexibility, suspension stiffness and damping nonlinearity, and rubber bushing nonlinearity. The dynamic model for frame and suspension have been developed with discrete element method and lumped mass method, respectively. Then, the flexible frame model has been verified through the mode shape and frequency calculated by finite element simulation. And the rigid-flexible coupling nonlinear dynamic model of a light commercial vehicle has been verified with Adams simulation and testing results. Furthermore, the influence of vehicle speed and the height of speed bump, suspension stiffness and damping, as well as cargo weight and distribution on vehicle system dynamics is analyzed with bifurcation diagram, time history, frequency, phase diagram and Poincare section. The results show the significant and complex effects on the nonlinear vibration of vehicle system, especially the nonlinear damping and the flexible frame.

Study on nonlinear dynamic characteristics of a two-speed transmission system at low speed.

A pure shear mechanical model of low gear of six-degree-of-freedom two-speed transmission system is established by using lumped parameter method. The Runge-Kutta method is used to numerically solve the aforementioned nonlinear system. The variation of transmission error between gears is analyzed by using global bifurcation, time domain diagram, phase diagram and Poincare cross section. Moreover, the transfer error bifurcation characteristics of the solar wheel and the first planetary wheel under different gear moduli are investigated. The results show that: by taking the excitation frequency as the control parameter, the system includes period-1 motion, period-2 motion, quasi-periodic motion, multiperiodic motion, and chaotic motion. With the increase of gear modulus, the system mainly presents chaotic motion in the medium frequency range (0.5<ωh≤2). It shows stable period-1 motion in the high frequency range (2<ωh≤3), and the higher the modulus, the wider the high frequency range of period-1 motion. The research results can provide reference for the design and optimization of this kind of two-speed transmission system in the future.

Phase Equilibria and Interdiffusion in the Ternary System Epoxy Oligomer-Polysulfone-Alkyl Glycidyl Ether.

Phase equilibria, interdiffusion and structure in the initial uncured mixtures of epoxy oligomer-polysulfone-alkyl glycidyl ether were studied. Binodal curves were constructed on isothermal sections of the ternary phase diagram. Thermodynamic mixing parameters were calculated and spinodal curves were plotted. The interdiffusion coefficients of components, establishing the technological modes of mixing the components, were determined. To validate the phase diagram, the phase structure of mixtures, the composition of which at a temperature of 40 °C corresponds to heterogeneous and homogeneous regions, was studied.

Microstructure evolution at the interface between Cu and eutectic Sn–Bi alloy with the addition of Ag or Ni

The study investigated the growth kinetics and rate-controlling processes of intermetallic layers formed at the interface between Cu and eutectic Sn–Bi alloys with Ag or Ni addition at solid-state temperatures. Isothermal sections of the equilibrium phase diagram were calculated to understand phase stability at the interface. The thicknesses of the intermetallic layers were plotted against annealing time, and a power function equation with an exponent slightly smaller than 0.25 described their relationship, indicating boundary diffusion with grain growth as the predominant control mechanism. The relationship between the exponent and annealing temperature suggested that the grain growth in the intermetallic layer followed an approximate parabolic law. The eutectic microstructure in Sn–57Bi–1Ag and Sn–57Bi–1Ni alloys changed with annealing, with differences in the Bi region width. However, the contact surface area between the Bi region and Cu6Sn5 compound was similar in both alloys. Activation enthalpies for the rate-controlling process of intermetallic layer growth were evaluated, providing insights into the energy barrier for atomic diffusion or transport across the interface.

Growth behavior of intermetallic layers at the interface between Cu and eutectic Sn–Bi by grain boundary diffusion with the grain growth at solid-state temperatures

The growth kinetics and rate-controlling processes of intermetallic layers formed in Cu/(Sn-58 wt% Bi) diffusion couples were investigated. Isothermal annealing of diffusion couples was conducted in the temperature range of 363–393 K for various times up to 384 h. In the diffusion couple, an intermetallic layer composed of Cu6Sn5 with irregular scallop shapes and Cu3Sn with relatively uniform thickness forms at the Cu/(Sn–Bi) interface. Isothermal sections of the equilibrium phase diagram in the ternary Bi–Cu–Sn system were calculated at the isothermal annealing temperatures and the peak temperature of the reflow process by a CALPHAD (calculation of phase diagrams) method. The diffusion path passes through the three-phase tie-triangle, including Cu6Sn5 and Cu3Sn. The obtained thicknesses were plotted against the annealing time, and a power function equation was found to describe their relationship. The values of the exponent in the power function were close to 0.25, indicating that the layer growth was predominantly controlled by boundary diffusion with the grain growth. Furthermore, the exponent values were relatively insensitive to the annealing temperature. The relationship between the exponent and the annealing temperature was analyzed, and it was concluded that the grain growth in the intermetallic layer followed a parabolic law. The growth and morphology evolution of the intermetallic compound and Sn–Bi eutectic microstructure at the interface were depicted, shedding light on the widening of the eutectic microstructure. Additionally, the activation enthalpy for the rate-controlling process of intermetallic layer growth at solid-state temperatures was evaluated using a least-squares method, providing insights into the energy barrier for the diffusion or transport of atoms across the interface. This study contributes to a better understanding of intermetallic layer formation and growth in Cu/(eutectic Sn–Bi) diffusion couples, offering valuable information for developing reliable solder joints and high-temperature solders.

Critical Evaluation and Thermodynamic Re-Optimization of the Si-P and Si-Fe-P Systems.

Thermodynamic modeling of the Si-P and Si-Fe-P systems was performed using the CALculation of PHAse Diagram (CALPHAD) method based on critical evaluation of available experimental data in the literature. The liquid and solid solutions were described using the Modified Quasichemical Model accounting for the short-range ordering and Compound Energy Formalism considering the crystallographic structure, respectively. In the present study, the phase boundaries for the liquidus and solid Si phases of the Si-P system were reoptimized. Furthermore, the Gibbs energies of the liquid solution, (Fe)3(P,Si)1, (Fe)2(P,Si)1, and (Fe)1(P,Si)1 solid solutions and FeSi4P4 compound were carefully determined to resolve the discrepancies in previously assessed vertical sections, isothermal sections of phase diagrams, and liquid surface projection of the Si-Fe-P system. These thermodynamic data are of great necessity for a sound description of the entire Si-Fe-P system. The optimized model parameters from the present study can be used to predict any unexplored phase diagrams and thermodynamic properties within the Si-Fe-P alloys.

Formation and structure of 1/1 cubic approximants in the Cd-Mg-Ce system: The identification of a new structural variant

The stability region of the 1/1 cubic crystalline approximant to icosahedral quasicrystal in the Cd-Mg-Ce system was investigated in detail. The partial isothermal section of the ternary phase diagram at 673 K was determined in the range from 0 to 18 at% Ce, where it was shown that the approximant spans a wide compositional range of Cd57−86Mg0−29Ce14–15. Mg addition was found to shift the stability region to lower temperatures. Besides, the approximant was found to be in equilibrium not with the Cd-Mg solid solution but with (Cd,Mg)17Ce2 and (Cd,Mg)11Ce compounds as opposed to the previous work [J. Alloys Compd. 822 (2020) 153541]. Based on the diffraction data (both X-ray and electron), to our surprise, a new variant of 1/1 cubic approximant was identified within the compositional range. The prototype Cd37Ce6 structure (space group Pn3̅) which dominates near the Cd-rich end was found to be partly taken over by the Cd25Eu4-type structure (space group Fd3̅) with a doubled unit cell in the higher-Mg part of the compositional range. The atomic structure with both Pn3̅ and Fd3̅ symmetries were determined by means of single-crystal X-ray diffraction measurement. Their refined atomic structures were compared and the preferential sites for Mg substitution are revealed.

Synthesis of Isostructural Intermetallic Sn-Pb-Bi-Pt Platform Materials for Catalytic Investigations.

The isostructural region (Sn,Pb,Bi)Pt has been established over a wide range of the quasi-ternary section of the quaternary phase diagram. A synthesis protocol was developed, and single-phase compounds were thoroughly characterized, revealing linear relationships between the volume of the unit cell and the substitution degree for the NiAs type of crystal structure. Together with the already established (Pb,Bi)Pt series, the isostructural cut at 50 atom % Pt forms an ideal platform to independently investigate the influence of electronic and structural properties for physical and chemical applications, such as electrocatalysis. The three binary endmembers SnPt, PbPt, and BiPt are active materials in a variety of electrocatalytic oxidation and reduction reactions such as methanol oxidation and oxygen reduction, respectively. By gradual substitution, a fully independent tuning of interatomic distances and electronic densities can be achieved without altering the crystal structure. This unique adaptability is gated behind the requirement of extended homogeneity ranges of at least quaternary intermetallic compounds. Here, we present this new platform for systematic investigations in (electro) catalysis.

Phase equilibria of the Sb2Te3+2BiI3↔Bi2Te3+2SbI3 reciprocal system: Synthesis and characterization of the cation-substituted Bi1−xSbxTeI solid solutions

The phase equilibria of the Sb2Te3+2BiI3↔Bi2Te3+2SbI3 reciprocal system have been investigated over the entire concentration range using differential thermal analysis (DTA), powder X-ray diffraction (PXRD), and scanning electron microscopy (SEM) techniques. Liquidus surface projection, solid-phase equilibrium diagram at 300 K and a number of isopleths sections of phase diagram were constructed based on experimental results and literature data. The primary crystallization areas of all the existing phases, their homogeneity ranges, as well as, types and coordinates of non- and monovariant equilibria were revealed. It is determined that the BiTeI−SbTeI section of this reciprocal system is non-quasi-binary due to the incongruent melting of one of the initial ternary compound. However, it is stable at subsolidus and forms wide areas of solid solutions based on the initial compounds. Additionally, dielectric functions and Raman spectra of Bi1−xSbxTeI (x=0; 0.05 and 0.1) phases were studied. The nature of the dependence of the dielectric function on the photon energy was identified based on the obtained ellipsometric data, while Raman spectra show that no structural changes were observed with an increasing concentration of antimony in the solid solution.

Nonlinear dynamics analysis of multifactor low-speed heavy-load gear system with temperature effect considered

Low-speed and heavy-load gears generate a lot of heat during meshing transmission, which leads to thermal deformation of the gears and affects the transmission performance of the gear system. It is of great significance to explore the influence law of temperature effects on the nonlinear dynamics of the gear system. Based on the principle of thermal deformation, taking into account the temperature effect and nonlinear parameters, including time-varying meshing stiffness, tooth side clearance as well as comprehensive errors, a nonlinear dynamic model of the gear system of spur cylindrical gear system is established. The Runge–Kutta method is used for numerical solution, the effect of temperature variation and time-varying stiffness coefficient on the bifurcation characteristics of the gear system is analyzed by combining bifurcation diagram, maximum Lyapunov index diagram, phase diagram and Poincare section diagram. The results show that the gear system exhibits complex nonlinear dynamics with the consideration of temperature effects, including four states of single-fold periodic motion, multi-fold periodic motion, and bifurcation and chaotic motion. The influence of temperature variation on the nonlinear characteristics of the gear system is closely related to the value of the time-varying stiffness coefficient. The effect of temperature variation on the bifurcation characteristics of the system is obvious when the value of the time-varying stiffness coefficient s is in the range of 0.4 < s < 0.8. The relevant conclusions can provide references for the design of gear systems under special working conditions.

Serpentinite dehydration at low pressures

Petrographic observations combined with mineral compositional analyses constrain the phase relations of prograde metamorphosed serpentinites in the Bergell contact aureole (Italy). In a 1500 m profile perpendicular to the north-eastern edge of the Bergell intrusion, seven dehydration reactions ran to completion. Three previously undocumented reactions have been identified within 70 m of the intrusive contact: olivine + anthophyllite = orthopyroxene + H2O, tremolite + Cr–Al-spinel = olivine + Mg-hornblende + H2O and chlorite = olivine + orthopyroxene + Cr-Al-spinel + H2O. Petrological analysis indicates that these reactions occur over a narrow range of pressure and temperature, 300 ± 30 MPa and 720 ± 10 °C respectively. Computed phase diagram sections reproduce the observed mineral parageneses with one notable exception. Due to the underestimation of aluminium and sodium contents in Ca-amphibole models, plagioclase is predicted above 700 °C instead of Mg-hornblende. In comparison with natural grains, the aluminium content of computed chlorite compositions is overestimated for low grade parageneses while it is underestimated near the upper thermal stability limit of chlorite. In the computed sections, Fe partitioning relative to Mg between olivine and other silicates, suggests a clear preference for Fe in olivine, that therefore shows lower Mg#s. In contrast, microprobe analyses of natural mineral pairs indicate that orthopyroxene, Mg-hornblende and anthophyllite have lower Mg#s than equilibrium olivine. The inferred thermal profile of the metamorphic aureole is not consistent with simple heat conduction models and indicates a contact temperature of ~ 800 °C, which is 120–230 °C higher than previously estimated. Petrography also reveals extensive retrograde overprint of the prograde parageneses within 200 m of the contact. Retrogression is related to metamorphic fluids that were released by dehydration reactions during contact metamorphism and magmatic fluids expelled from the tonalite intrusion. The thermal gradient between the intrusion and the country rocks induced hydrothermal circulation of these fluids throughout the contact aureole, which beyond peak metamorphic conditions caused retrograde overprint of the prograde parageneses. The proposed phase relations for low and high pressures, and in particular, the transition from tremolite to Mg-hornblende, provides a complete representation of hydration and dehydration processes in serpentinites in subduction zones, along deep oceanic transform faults, and at passive continental margins. The latter has new implications, specifically for subduction initiation.

Thermodynamics of heterogeneous equilibria in the In-In2 O3 system using Knudsen effusion mass spectrometry.

The In-In2 O3 system is regarded as a potential low-temperature source of gaseous indium oxide (In2 O) when obtaining functional materials by physical vapor deposition techniques. To date the vaporization thermodynamics of the system have been investigated in few studies, the results of which are contradictory. The study of the In-In2 O3 system was performed using Knudsen effusion mass spectrometry in the temperature range 930-1210 K, with a magnet mass spectrometer (MS-1301). Quartz effusion cells heated by a resistance furnace were employed. It was established that In(g) and In2 O(g) are the major vapor species over heterogeneous mixtures (In(l) + In2 O3 (s)) and the gaseous oxide In2 O is predominant. The partial pressures of the vapor species were determined and the quantitative vapor composition was calculated. Based on the experimental data, a p-x section of the In-In2 O3 system phase diagram at 1060 K was constructed. The standard enthalpies of reactions accompanying vaporization of the In and In2 O3 mixtures were evaluated using the second- and third-law methods. The standard enthalpy of formation of In2 O(g) was derived from the enthalpies of reactions obtained. The predominance of In2 O in the equilibrium vapor over heterogeneous mixtures (In(l) + In2 O3 (s)), along with its high partial pressure at relatively low temperatures, substantiate the In-In2 O3 system to be suitable for physical vapor deposition methods. The obtained results can be used for physical vapor deposition parameter adjustment and optimization. The standard enthalpy of formation of In2 O(g) obtained in an independent way in the present work is in good agreement with that from our previous In2 O3 (s) vaporization study.

Thermodynamic, Kinetic and Strength Calculation of High Zinc Containing Al-Zn-Mg-Cu Alloys

High zinc containing Al-Zn-Mg-Cu is the research focus of ultra-high strength aluminum alloy. In the present paper, the Al-Zn-Mg-Cu multi-component system is studied when the content of Zn is 10.5 wt.%, 11 wt.% and 12 wt.%, respectively. The vertical sections of phase diagrams are calculated by the thermodynamic method. The precipitation parameters of the η’ phase, including the density of precipitate, precipitate radius and volume fraction, are obtained by using the methods of kinetic calculations. The yield strength of Al-Zn-Mg-Cu alloy with different content of Zn is calculated by an empirical model containing a chemical element and a microstructure parameter. The calculated results of yield strength are verified by experimental data and provide primary guidance to developing Al-Zn-Mg-Cu ultra-high strength aluminum alloys.

High-resolution structural elucidation of extremely swollen lyotropic phases

Self-assembled lyotropic phases are important in a variety of applications, in particular microemulsions are essential for formulation science. A spectacular situation arises when microemulsions are made to swell by systematically increasing the bending modulus of the surfactant film separating the oil and water regions. In an attempt to realize such extremely swollen microemulsion phases, Peter et al. [Phys. Rev. Lett., 76 (1996) 3866] found a variety of lyotropic phases including a long-range ordered three-dimensional cubic phase over a narrow section of the complex phase diagram of a pseudo-quaternary system composed of decane, brine, octanol, and sodium dodecyl sulfate. In this work, the same region of the phase diagram was reinvestigated using high-resolution small-angle X-ray scattering (HR-SAXS) and rheo-SAXS, which is an important technical aspect for homogenizing the sample and orienting the structural units. Whilst the formation of a swollen two-dimensional hexagonal phase was observed, the structural features of a cubic phase were not detected. The long correlation lengths noted prior were also seen here, over 2000 nm for the hexagonal phase, taken from rheo-SAXS measurements. Based on the measurements covering more than three orders of magnitude in scattering vector, the structure appeared to be an organization of elongated swollen emulsion droplets, which could form an interconnected structure, dense liquid-like order, or further order into a hexagonal morphology with unusually large lattice spacings for a surfactant system.

Thermodynamic and DFT modeling in quaternary Co-based Heusler phase space: Understanding the interplay between disorder, bonding, and magnetism

Co-based Heusler phases, for example Co(Cr,Fe,Al), are considered as potential half-metallic ferromagnets with full spin polarization at the Fermi level and are therefore not only interesting from a fundamental point of view but also for their prospective technological exploitation. For successful materials design via selection of candidates towards desired properties as well as practical synthesis, knowledge of the relevant thermodynamic phase diagrams is an important aspect. However, the materials of interest constitute quaternary systems, where such knowledge is scarce. The importance of thermodynamic understanding is underlined by previous experimental findings, which report that the phase formation of the desired structurally ordered Co(Cr,Fe,Al) is not straightforward due to thermodynamic instabilities. In this work, we revisit the quaternary region of the CoCr-CoAl-CoFe section of the thermodynamic phase diagram through DFT and thermodynamic calculations. The regular solution model indicates the formation of an immiscibility region centered around a pseudoternary critical point at Tc = 1412 K and the composition CoFe0.2Cr0.4Al0.4. FP-LAPW ab initio calculations of the enthalpy of mixing show an energetically favorable minimum at the CoCr0.125Fe0.25Al0.625 composition and a local maximum around CoFe0.125Cr0.375Al0.5 which corresponds to the region of immiscibility and matches the area of the binodal/spinodal decomposition resulting from the regular solution model. We discuss three types of substitution: Al for Cr, Al for Fe, and Al for Cr/Fe with special focus on the formation of different structural motifs, specifically on the order- and disorder, depending on the Cr/Fe ratio. Chemical bonding and magnetic properties of selected compositions are calculated and analyzed. Our results underline the significance of careful consideration of thermodynamic phase formation for materials design and consequently for machine learning approaches towards practical realization of functional materials.

Kinetics and thermodynamics of compound growth due to reactive diffusion between solid Cu and binary Bi-Sn alloys

The growth behavior of compounds for the reactive diffusion between solid Cu and molten binary Bi-Sn alloys was experimentally examined using semi-infinite diffusion couples prepared by an isothermal bonding technique. Isothermal annealing of (Biy-Sn1-y)/Cu diffusion couples with Bi mol fraction of y = 0.27–0.46 was conducted in the temperature range of 453–603 K (180–330 °C) for various times up to 345.6 ks (96 h). In the diffusion couple with y = 0.44, an intermetallic layer composed of Cu6Sn5 with irregular scallop shapes and Cu3Sn with relatively uniform thickness forms at the (Bi-Sn)/Cu interface at 453–523 K (180–250 °C). In contrast, at 563–603 K (290–330 °C), the intermetallic layer consists of only Cu3Sn. Isothermal sections of the equilibrium phase diagram in the ternary Bi-Cu--Sn system were calculated at 453–603 K (180–330 °C) by a CALPHAD (calculation of phase diagrams) method. For the diffusion couple with y = 0.44, the diffusion path passes through the three-phase tie-triangles containing Cu6Sn5 and/or Cu3Sn in the isothermal section at 523 K (250 °C), but through only that containing Cu3Sn in the isothermal section at 603 K (330 °C). As a result, for y = 0.44, the intermetallic layer is composed of Cu6Sn5 and Cu3Sn at 453–523 K (180–250 °C), whereas it consists of only Cu3Sn at 563–603 K (290–330 °C). The mean thickness of the intermetallic layer is proportional to a power function of the annealing time, and the exponent of the power function is mostly smaller than 0.5. Such smaller values of the exponent mean that the layer growth is controlled by boundary diffusion across the intermetallic layer. Adopting the common value of 0.30 as the exponent of the power function for the Cu3Sn layer at 563–603 K (290–330 °C), we obtain a value of 17.9 kJ/mol for the activation enthalpy of the proportionality coefficient of the power function.

Stability of High Entropy Alloys to Spinodal Decomposition

When a high entropy alloy (HEA) system contains a single binary miscibility gap, the gap spreads across the entire composition space of the system. Beneath the miscibility gap is a spinodal hypersurface above which HEAs are stable to a continuous change of phase via spinodal decomposition. When there are additional binary miscibility gaps, the stability limits appear separately at high temperature but combine on cooling to form a continuous surface that may contain a cone point, an important feature for the design of age hardening alloys. In this work, an understanding of how spinodal surfaces form, combine, and develop critical features is obtained by investigating several ternary systems each with three binary miscibility gaps. Because their topology is the same, bisection isopleths and isothermal sections of ternary phase diagrams given in this work will help interpret calculated bisection isopleths and isotherms of 5- and 6-dimensional HEA phase diagrams.

Phase Evolution During Heat Treatment of Nb3Sn Wires Under Development for the FCC Study

In recent years, the phase formation sequence during heat treatment of Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn wires, and the influence of the microstructure and compositional homogeneity of Nb <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn on in-field critical current (I <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sub> ), have received increasing attention. For RRP wires, the importance of understanding and managing the formation of the ternary phase nausite has been demonstrated. However, a published Cu-Nb-Sn phase diagram including this phase is still not available; and conductor development for the Future Circular Collider (FCC) study has introduced a variety of less-studied internal tin wire layouts. In this article, a study of phase transformations in the ternary Cu-Nb-Sn system is summarized, and selected isothermal sections of the re-evaluated phase diagram are presented. The phase transformations during low-temperature heat treatment steps of wires developed for the FCC study are also presented and analyzed in comparison to established RRP conductors.

Construction of P–T–t paths for eclogite in the Tongbai orogen by combining phase equilibria modelling with zircon inclusion composition

AbstractThe interpretation of metamorphic ages for zircon domains in eclogite remains challenging because of the uncertainties in interpreting their rare earth element (REE) patterns and mineral inclusions. This has seriously hindered the construction of robust pressure (P)–temperature (T)–time (t) paths for eclogites from collisional orogens. In this study, a composite approach is used to obtain a reliable P–T path for eclogite from the Tongbai orogen and quantitatively attribute zircon U–Pb ages to specific P–T intervals. An integrated study using isochemical phase diagram section (pseudosection) modelling, multi‐equilibrium thermobarometry, and the Zr‐in‐rutile thermometry with petrographic observations indicates that the target eclogite experienced multistage metamorphic evolution. The evolution is characterized by a clockwise P–T path with compressional heating for peak eclogite facies metamorphism at 588 ± 20°C and 26.7 ± 2.8 kbar and two stages of isothermal decompression from an early stage of amphibole eclogite facies metamorphism at 15–10 kbar to a late stage of amphibolite facies metamorphism at pressures of &lt;10 kbar. Metamorphic zircon domains in eclogite and quartz vein show relatively flat patterns of heavy REE without notable Eu anomalies but different cathodoluminescence responses and middle REE (MREE) contents. This indicates their growth in different stages of eclogite facies metamorphism, which are categorized into two groups. The first group is composed of bright rims or homogenous grains that are characterized by low MREE contents, suggesting the existence of abundant amphibole during the metamorphism. The compositional isopleths of amphibole inclusions indicate that this group of zircon domains would form by hydration during crustal exhumation to amphibole eclogite facies at 240 ± 2 Ma. The second group consists of dark sector mantles and shows high MREE contents, indicating the prograde to peak metamorphism with significant decomposition of amphibole or lawsonite during crustal subduction to eclogite facies at 245 ± 2 Ma. Therefore, the combination of the isopleth thermobarometry of mineral inclusions with the Zr‐in‐rutile thermometry and the zircon REE partitioning is an effective means to link the metamorphic P–T conditions to the ages of metamorphic zircons in the different stages of collisional orogeny.

Phase equilibrium in the system Y-Ni-In at 870 K

Interaction of the components in Y ‑ Ni ‑ In system was investigated by X-ray powder methods and isothermal section of phase diagram was constructed at 870 K in full concentration range. The samples were synthesized in an arc-furnace on a water-cooled Cu-plate under an argon atmosphere and annealed in silica tubes at 870 K for one month. The phase analysis was performed by X-ray powder diffraction method. Twelve ternary compounds, namely YNi 9 In 2 (YNi 9 In 2 -type structure), Y 1-1 . 40 Ni 4 In 1-0 . 60 (MgCu 4 Sn-type structure), YNiIn 2 (MgCuAl 2 -type structure), Y 4 Ni 11 In 20 (U 4 Ni 11 Ga 20 -type structure), YNi 1 . 00-0 . 50 In 1 . 00-1 . 50 (ZrNiAl-type structure), Y 2 Ni 2 In (Mn 2 AlB 2 -type structure), Y 2 Ni 1 . 78 In (Mo 2 FeB 2 -type structure), Y 5 Ni 2 In 4 (Lu 5 Ni 2 In 4 -type structure), Y 11 Ni 4 In 9 (Nd 11 Pd 4 In 9 -type structure), Y 12 Ni 6 In (Sm 12 Ni 6 In-type structure), Y 13.84 Ni 3.19 In 2.97 (Lu 14 Co 3 In 3 -type structure), ~Y 3 Ni 0.05 In 0.95 (AuCu 3 -type structure) exist in the Y ‑ Ni ‑ In system at the temperature of annealing. Compound Y 3 Ni 2.26 In 3.74 exists at higher temperature. The substitution of Ni for In was observed for YNi 1.00-0.50 In 1.00-1.50 and In for Y in the case of Y 1-1,40 Ni 4 In 1-0,60 compound. Besides, yttrium can enter the structure of NiIn (CoSn-type) leading to formation of including-subtraction type solid solution, which is stable for 0 ‑ 8 at. % Y. The composition of this solid solution can be described by the formula Y 0-0 . 16 NiIn 1-0 . 93 . The inclusion of yttrium and indium atoms in position (2 e ) with the simultaneous exclusion of a small amount of indium atoms from position (1 a ) takes place in the homogeneity range of this solid solution. The character of component interaction in the ternary Y ‑ Ni ‑ In system is similar to other related ternary system R ‑ T ‑ In ( R – rare earth of the yttrium subgroup). The common feature of all these systems is the existence of large number isotypical ternary compounds, the formation of homogeneity range for compounds with ZrNiAl and including-subtraction type solid solutions based on the binary compound NiIn. Keywords: yttrium, indium, nickel, phase equilibria, ternary compound, crystal structure.