Papers by Keyword: Ternary System

Abstract: With available melting point and hardness, the Bi-based filler alloy is considered as one choice of high-temperature Pb-free solder. Phase diagram can play an important role in the design of new type of Pb-free solder.In the present work, the thermodynamic assessments of the Au-Nd and the Au-Lu binary systems have been carried out by the Calculation of Phase Diagram (CALPHAD) method based on the available experimental data. The Gibbs free energies of the solution phases were described by subregular solution models with the Redlich-Kister equation, and those of the intermetallic compounds were described by sublattice models. A set of self-consistent and reasonable thermodynamic parameters is obtained for the binary systems, which describes the Gibbs energies of the solution phases and the intermetallic compounds phases. Additionally, combined the reported Bi-Au, Bi-Lu and Bi-Nd binary systems, the thermodynamic database of the Bi-Au-Lu and the Bi-Au-Nd ternary systems have been developed, which will provide important thermodynamic information for the phase equilibria of the multicomponent Bi-based alloy systems.

Abstract: The phase equilibria in the Fe-Nb-V ternary system were investigated by means of optical microscopy, electron probe microanalysis. One isothermal section in the Fe-Nb-V ternary system at 1050 °C was firstly experimentally established. Present experimental results indicate that: (1) there is a large (Nb, V) continuous bcc solid solution; (2) there are the larger solubilities of V in the FeNb and Fe₂Nb phases. The newly determined phase equilibria in this system will provide important support for the development of microalloyed steels.

Abstract: The addition of the rare earth elements into the Ag-based filler alloy, which is typical and important, can control and eliminate the negative effect of impurity elements, and furthermore, it improves the spreading property of the Ag-based filler alloy. Phase diagram provides an important direction for materials design of the Ag-based filler alloy. Thus it is necessary to investigate the phase diagrams and construct the thermodynamic database. On the basis of this background, thermodynamic assessments of the Au-Gd, Tb binary systems were carried out by using the CALPHAD (Calculation of Phase Diagrams) method based on the experimental data including thermodynamic properties and phase equilibrium. The Gibbs free energies of the solution phases were described by sub-regular solution models with the Redlich-Kister equation, while all of the intermetallic compounds were described by sub-lattice models. A consistent set of thermodynamic parameters was derived from describing the Gibbs free energies of each solution phase and intermetallic compound. The calculated phase diagram achieved consistency with the available experiments. Then combined with the assessed relevant binary systems, the Ag-Au-Gd, Tb ternary systems have been predicted. The thermodynamic database of these ternary systems has been developed to present the significant information for the design of Ag-based filler alloys.

Abstract: The isothermal solubility of the ternary system K+,Mg2+/B4O72-—H2O at 25°C has been studied and the phase diagram is determined. The results show that the system is of the simple eutonic type and can be in metastable equilibrium state within 8—16 hours. The phase diagram consists of two solubility branches corresponding to the crystallization areas of K2B4O7•4H2O and MgB4O7•9H2O. The composition of the eutonic point is MgB4O7,0.5279%(Wt%) and K2B4O7,13.9629%(Wt%) respectively. The replicate experiments proved that the phase transformation of hungtsaoite (MgB4O7•9H2O) occurs after a 20 hours epuilibrium.

Abstract: A method has been developed for calculating diffusion profiles in ternary systems by using effective interdiffusion coefficients of components and Boltzmanns solution for diffusion equation with variable diffusion coefficient. Using this method the concentration profiles for several diffusion couples in the systems Fe-Co-Ni and Cu-Fe-Ni are calculated as examples and some peculiarities of these calculations are discussed, particularly, how to solve some possible difficulties, which may sometimes arise at calculation procedures. It is shown that having the data on effective interdiffusion coefficients and their concentration dependence for at least two components in a ternary diffusion couple, the concentration profiles for all three components can be calculated with good accuracy.

Abstract: Possible interrelations between diffusion paths and interdiffusion coefficients in the system Fe-Co-Ni are analyzed. It is found that the apparition of a straight line shape of diffusion paths imposes strong demands on the values of the conventional interdiffusion coefficients calculated from the experimental data. The possible consequences of this finding are discussed.

Abstract: An exact description of the distribution of 2D bimetallic clusters deposited on a square substrate has been obtained via an exact inventory algorithm. We show that several features of the monometallic distribution can be altered by the presence of a second species within the clusters. The diagram of ground-state morphologies of such clusters is built as a function of the chemical interactions between both components. As a consequence, the maxima in the cluster size distribution that indicate the magic numbers can be smoothened or shifted during co-deposition as a function of the composition of the two-component phase.

Abstract: The metastable phase equilibrium in the ternary system containing potassium, lithium and chloride ions was studied at 298.15 K using an isothermal evaporation method. The solubility, density and refractive index of the equilibrated solution were measured. The crystalloid forms of the solid phase were determined using a schreinermarks wet residue method. On the basis of the experimental data, the metastable equilibrium phase diagram and the physicochemical properties vs composition in the ternary system at 298.15 K were plotted. The experimental results show that this system is of a simple eutectic type system, no double salt or solid solution formed at 298.15 K. The phase diagram consists of one invariant point, two uninvariant curves, and two crystallization regions. The crystallization regions correspond to potassium chloride (KCl) and lithium chloride monohydrate (LiCl·H₂O), respectively. Salt KCl has the largest crystallization field, whereas salt LiCl·H₂O has the smallest crystallization field. Salt LiCl has strong salting-out effect on salt KCl.

Abstract: An empirical approach to the description of diffusion paths in the ternary system Fe-Co-Ni is developed. It is shown that the experimentally determined diffusion path in this system can be described by the universal function, which contains two parameters, extracted from experimental data. The values of these parameters and their possible dependence on initial compositions of diffusion couples are discussed. Using the universal function, typical diffusion paths for the system Fe-Co-Ni have been calculated. It is shown that the calculated diffusion paths are in a qualitatively good agreement with the available experimental data.

Abstract: Ab initio electronic structure theory has achieved considerable reliability concerning predictions of physical and chemical properties and phenomena. It provides understanding of matter at the atomic and electronic scale with an unprecedented level of details and accuracy. In the present contribution, the electronic structure theory and state-of-the-art ab initio calculation methods in solids are briefly reviewed and the application of the calculated total energy differences between various phases (lattice stabilities) is illustrated on construction of phase diagrams by the CALPHAD (CALculation of PHAse Diagrams) method in systems containing phases with complex structures, as e.g. Laves phases or sigma phase. Particular examples include description of the Laves phases in the Cr-Nb, Cr-Ta and Cr-Zr systems, sigma-phase in the Fe-Cr system and prediction of the phase composition of ternary Fe-Cr-Mo system and super-austenitic steels. It is shown that the utilization of ab initio results introduces a solid basis of the energetics of systems with complex phases, allows to avoid unreliable estimates and extrapolations of Gibbs energies and brings more physics into the CALPHAD method.