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The Cu-Sn-P phase diagram is essential for understanding the metallurgical phenomena of Cu-Sn bronze, brazing filler metals, and Sn-Cu lead-free solder. In this study, the solidus, liquidus temperatures and solubilities of P in the Cu-rich of the Cu-P system were determined using the electron probe micro-analyzer and differential scanning calorimetry. In addition, the thermodynamic assessment of the Cu-Sn, Cu-P, Sn-P, and Cu-Sn-P systems was carried out based on the results of previous studies and experiments of the current study. An associate-solution model was employed for the liquid phase, and an order/disorder model was employed for the bcc-based phase. The calculated phase diagrams and thermodynamic properties were in good agreement with the experimental data. The parameter set reproduced the Cu-Sn-P ternary phase diagrams without introducing ternary parameters into the liquid phase. Thus, the proposed model can reproduce the full-range of the compositional phase diagram of the Cu-Sn-P system. [ABSTRACT FROM AUTHOR]

As nickel-based heat-resistant alloys contain small amount of boron and carbon, it is imperative to study their phase diagrams and thermodynamic properties to understand the behavior of carbon and boron. In this study, the solubilities of carbon and boron at the face-centered cubic (fcc) and liquid phase transition temperatures of Ni–B and Ni–B–C systems were determined using the diffusion couple technique and differential scanning calorimetry. In addition, a thermodynamic assessment of the Ni–B, Ni–C, and Ni–B–C systems was conducted based on the results of previous studies and experiments of the current study. An associate model was employed for the liquid phase, and a compound energy model was employed for the fcc phase. The calculated results agreed well with the experimental data without the introduction of ternary parameters. Metastable two-phase separation in the liquid phase was predicted on nickel-rich side in the Ni–B system at low temperature, which can be related to the phase separation or compositional modulation of Ni–B amorphous alloys. Thus, the present model can reproduce the phase diagram of metal-boron systems. [ABSTRACT FROM AUTHOR]

This study reports the thermodynamic assessment of the temperature and pressure dependence of molar volume of Cu and Zn, as well as their P–T phase diagrams based on the CALPHAD approach. The molar volume of fcc -Cu, hcp -Zn, and liquid phases as a function of both temperature and pressure was directly assessed from the data reported in the literature by implementing the CALPHAD-compatible equation of state (EOS). This EOS incorporates the quasi-harmonic model to eliminate the spurious predictions of negative heat capacity and thermal expansion at high pressure. Furthermore, the P–T phase diagram of each element was determined on the basis of the experimental results and calculated parameters. The experimentally estimated thermodynamic values are in good agreement with the calculated results. [ABSTRACT FROM AUTHOR]

Highlights: [•] The Bi–Mn phase diagrams in high magnetic fields were calculated. [•] The magnetic field effect for the decomposition temperatures was investigated. [•] The calculated phase diagram is in good agreement with experimental data. [•] At 49T, the areas of BiMn1.08 +liquid were vanished. [ABSTRACT FROM AUTHOR]

Abstract: Phase equilibria and thermodynamic properties of the KCl–K2CO3–NaCl–Na2CO3 system were analyzed on the basis of the thermodynamic evaluation of the KCl–NaCl,KCl–K2CO3,NaCl–Na2CO3,K2CO3–Na2CO3 and KCl–K2CO3–NaCl–Na2CO3 systems. The Gibbs energies of individual phases was approximated by two-sublattice models for ionic liquids and crystals. Most of the experimental information was well described by the present set of thermodynamic parameters. The lowest monovariant eutectic temperature in the KCl–NaCl–Na2CO3 system is located at 573 ∘C, with a composition of X Na2CO3 =0.31,X KCl=0.35 and X NaCl=0.34. [Copyright &y& Elsevier]

Highlights • Interfacial energy between γ and γ′ phase in TMW-4M3 is about 75 mJ/m2 around 1400 K. • Off-diagonal contribution is crucial to interfacial energy estimation in TMW-4M3. • Thermodynamic calculations agree with interfacial energy from coarsening kinetics. Abstract The interfacial energy between the γ and γ′ phase in Ni-Co base superalloy TMW-4M3 was investigated using both a kinetic analysis of experimental data and a thermodynamic analysis. The coarsening rate of γ′ precipitates during the aging treatment process was analyzed using extended Lifshitz-Slyozov-Wagner theory, including the contribution of a full diffusion matrix with a thermodynamic calculation. The interfacial energies calculated from the coarsening kinetics using only the diagonal components were half as large as those using the off-diagonal contributions as well. The interfacial energy with full diffusion matrix contributions is about 75 mJ/m2 between 1373 and 1413 K. In addition, the interfacial energy was also analyzed on the basis of the extended Becker's model (EBM), and the results, which ranged from 73.9 to 76.3 mJ/m2, showed good agreements with those from the coarsening kinetics. A comparison of the interfacial energy between TMW-4M3 and several Ni base superalloys indicated an identical tendency of higher interfacial energy with a larger Ti/Al ratio. The off-diagonal terms of a diffusion matrix are very important in analyzing the coarsening kinetics of γ′, and the γ/γ′ interfacial energy estimation using the EBM is a suitable method for TMW-4M3. [ABSTRACT FROM AUTHOR]

Experimental investigation and thermodynamic evaluation of the Co–Ta binary phase diagram was carried out. Equilibrium compositions obtained in two-phase alloys and diffusion couples were measured by electron probe microanalyzer (EPMA). A very narrow λ 3(C36) + λ 2(C15) two-phase region is confirmed to be present around 26.5 at.% Ta at temperatures between 950 °C and 1448 °C. Equilibrium relationships above 1500 °C among the liquid, Laves (λ 1(C14), λ 2 and λ 3, whose stoichiometry is described by Co2Ta), μ(D8b) and CoTa2(C16) phases were investigated by microstructural examination in as-cast Co-(24–60 at.%)Ta alloys. The solvus temperature of the γ′ Co3Ta (L12) phase precipitated in the 5.8 at.%Ta γ(Co) and the peritectoid temperature of the Co7Ta2 phase in an 8.5 at.%Ta alloy were determined to be 1013 °C and 1033 °C, respectively, by differential scanning calorimeter (DSC). Fine precipitates of the γ′ phase precipitated in the γ (A1) matrix were observed by transmission electron microscope (TEM). Analyzing the present experimental results synthetically, the γ′ Co3Ta phase was identified to be a metastable phase, of which the γ/γ′ transition temperature of the stoichiometric Co3Ta alloy was estimated to be 2000 °C. Thermodynamic assessment of the Co–Ta binary system was carried out based on the present results as well as on experimental data in the literature. Calculated results of not only stable but also metastable equilibria were found to be in good agreement with the revised phase diagram. The evaluated stability of the metastable γ′ Co3Ta coincides with the enthalpy of formation (ΔH(γ'Co3Ta) = −23.44 kJ/mol) calculated by the ab initio method. [ABSTRACT FROM AUTHOR]