Diffusion is one of the key factors that controls the precipitation of Al3Li metastable phase in Al-Li alloys. In this work, the diffusivity data in fcc Al-Li binary alloys available in the literature were comprehensively reviewed and critically evaluated, the diffusion mobilities of Al and Li in the Al-Li fcc_A1 phase were then assessed based on the reliable experimental data and empirical equations in the literature. An early relationship that correlates the diffusion activation energy and the melting temperature was revisited for group I elements, Li, Na, and K, and was used to predict the diffusivity of fcc Li. One set of self-consistent atomic mobility parameters for the Al-Li fcc_A1 phase was obtained. The limited reliable experimental diffusivity data can be generally reproduced by the present model parameters. In combination with the related thermodynamic description, the atomic mobility parameters were further verified by simulating the diffusion profiles of ion implanted Al samples at different annealing times. The model parameters were also used to simulate the concentration profiles of a cylindrical diffusion couple and the solidification process of an Al-3.5 wt.% Li alloy.

In the present work, a series of ZrO2–TiO2–SrO ceramic samples were prepared through solid-state reactions, and the phase relationships at 1473 K were systematically characterized. For the TiO2–SrO binary system, the presence of Sr4Ti3O10 was confirmed and the binary system was reassessed through CALPHAD method by using both the latest experimental data and first-principles calculations. The thermodynamic parameters of the TiO2–SrO system were combined with those of the ZrO2–TiO2 and ZrO2–SrO systems, and a set of self-consistent thermodynamic parameters of the ZrO2–TiO2–SrO system was optimized according to our measurements. Finally, the isothermal sections at 1473 K and 1733 K, the vertical section of SrTiO3–SrZrO3 and the liquidus surface projection were calculated. The calculated results agree well with the available experimental data, which proves the self-consistency and reliability of the present thermodynamic database.

The phase equilibria of the Al-Ag-Si ternary system at 500 °C and 600 °C were investigated by X-ray powder diffraction (XRD) and electron probe microanalysis (EPMA). Three two-phase regions ((Al) + (Si), (Si) + Ag2Al, and (Si) + (Ag)) and two three-phase regions ((Si) + (Ag) + Ag2Al and (Si) + (Ag) + Ag2Al) were observed at 500 °C. The (Si) + Ag2Al and (Si) + (Ag) two-phase regions and (Si) + Ag2Al + liquid and (Si) + (Ag) + Ag2Al three-phase regions were identified in the isothermal section at 600 °C. A vertical section of the Al–Ag–Si system along Al0.6Si0.4–Al0.8Ag0.2 was investigated using differential scanning calorimetry (DSC) from which the temperatures of the phase-transition reactions were determined. The isothermal and vertical sections obtained in this study provide fundamental data for the thermodynamics of the Al–Ag–Si system and knowledge of the thermodynamics associated with aluminium-based alloys.

All available phase equilibria and thermodynamic data for (LiF + ReF3) (Re = La, Nd, Gd, Yb, Y, Lu) binary systems were carefully evaluated to obtain the optimized model parameters for all solid and liquid phases. A detailed review of the thermodynamic properties of all the pure and intermediate compounds in these binary systems provides a solid foundation for thermodynamic optimization. The enthalpies of mixing predicted at 1360 K for (50 mol% LiF + 50 mol% GdF3) and (50 mol% LiF + 50 mol% LuF3), using an empirical method, further enriched the experimental database. A modified quasichemical model in the pair approximation was used to model the molten salt phase of the (LiF + ReF3) (Re = La, Nd, Gd, Yb, Y, Lu) binary systems. All thermodynamic data available for the six binary systems were reproduced within the experimental error limits.

The comment (Joubert, 2022) regarding the controversial “NiW” phase detected in our previous study (Tang et al., 2022) was clarified in this work. Our previous conclusion about the presence of the “NiW” phase in the Ni-V-W ternary phase diagram is drawn without considering the contamination of C. In this work, alloys with a composition of Ni49V1W50 (at. %) were equilibrated at 1100 and 900 °C and characterized. The result showed that the NiW phase observed in the previous work (Tang et al., 2022) was actually Ni6W6C carbide, which resulted in misinterpretation of ternary phase constitutions in our previous studies about Ni-V-W (Tang et al., 2022) and Mo-Ni-W (Tang et al., 2020) systems. A new thermodynamic modeling of the Mo-Ni-W ternary system is performed by excluding the presence of “NiW” phase, and this set of parameters can describe the experimental results reasonably.

The phase equilibria at 500 °C of the Mg–Nd–Zn system in the region of 0–50 at.% Nd were investigated by combining the electron probe microanalysis (EPMA) and X-ray diffraction (XRD) of the equilibrated alloys. The partial isothermal section was constructed. Eight ternary phases (τ1 to τ6, τ8 and T-NdMg12) were found at 500 °C. Among them, τ8 is the newly found ternary compound. T-NdMg12 is the Zn-stabilized Mnl2Th-type NdMg12 phase. Its composition range was measured to be Nd7.6-7.7Mg84.5-88.7 Zn3.7-7.8. The homogeneity ranges of the seven ternary compounds (τ1 to τ6 and τ8) were well determined. The solubilities of the third elements in the binary compounds of the three binary systems were also well measured. The lattice parameters of the τ1, τ2 and τ5 phases were determined to be a = 0.9709 (3) nm/b = 1.1253 (4) nm/c = 0.9545 (3) nm at Nd7.8Mg57.0 Zn35.2 (τ1), a = 1.46234 (1) nm/c = 0.8706 (1) nm at Nd7.1Mg28.5Zn64.4 (τ2) and a = 2.0883 (2) nm at Nd16.7Mg18.5Zn64.8 (τ5), respectively.

Ascertainment of the nature of the slow relaxation processes observed after melting in glass-forming eutectic melts is the subject of this work. We claim that the diffusion processes nonlinearity in heterogeneous melt with inclusions of refractory stoichiometry is the origin of this phenomenon. The cause for this nonlinearity is the thermodynamic instability similar to one taking place at spinodal decomposition, and indispensable condition is the initially non-homogeneous. For confirmation of our devotes, we consider the model of liquid solution of a binary system, which evolution described by the Cahn–Hilliard equation with combined Gibbs potential assuming the presence of remains after melting stoichiometric phase. Exemplified by the Al–Y and Al–Yb alloys, using Gibbs potentials from standard database we show that subject to initial heterogeneity in these systems the instability can develop leading to the slow relaxation processes, and determine the regions of this instability in the phase diagrams.

The phase diagram and thermodynamic data of the H–Nb system are evaluated and re-assessed to improve the description of this system. This system is modeled up to a few MPa. Only the gas phase and the solid phases are considered in the present study. Since only a few data were available for the H–Nb–Zr ternary system, a new set of experimental data has been obtained in the present work. For the first time, the solubility of niobium into the ε-ZrH2 phase is found. In addition, Density Functional Theory calculations and the Special Quasirandom Structures method are used to determine the formation enthalpies of all the compounds and the mixing enthalpies in the different phases, respectively. Finally, the literature data as well as our experimental and calculated data are used for the Calphad modeling of the H–Nb–Zr system.

This study systematically investigates the phase equilibrium relations of the CaO–MgO–SiO2–13%Al2O3–50%TiO2 system in air at 1450 °C. Within the composition range, the coexistence of the liquid phase with anosovite and rutile, liquid-rutile (TiO2), liquid-anosovite (M3O5), liquid phase with anosovite and spinel, liquid-spinel, liquid phase with perovskite and spinel, and liquid-perovskite (CaTiO3) were found. Additionally, the 1450 °C isotherm in this system was obtained by comparing the experimental liquid phase results with the predicted results by FactSage 8.1. The experimental findings indicated that an increase in MgO content contributed to a higher concentration of MgTi2O5 in the anosovite solid solution. Notably, the predicted liquidus temperature was much lower than the experimentally determined liquidus temperatures within the primary of M3O5 and spinel area. This work would contribute to further refining the phase diagram of the titania-containing systems.