This paper provides a consistent thermodynamic data set for the whole Al-Nb-Ni ternary system via thermodynamic modeling. The order/disorder transitions between disordered bcc_A2 and ordered bcc_B2 phases as well as between disordered fcc-A1 and ordered L12 phases are treated using a two-sublattice model. The calculations indicate that the disordered and ordered phases can be described with a single equation. All of the experimental phase diagram data available from the literature are critically reviewed and assessed using thermodynamic models for the Gibbs energies of individual phases. Inconsistent experimental information is identified and ruled out. Optimal thermodynamic parameters are then obtained by considering reliable literature data. Comprehensive comparisons between the calculated and measured phase diagrams show that almost all the accurate experimental information is satisfactorily accounted for by the present thermodynamic description.

This paper provides a consistent thermodynamic data set for the whole Cr-Nb-Ni ternary system via thermodynamic modeling. All of the experimental phase diagram data available from the literature are critically reviewed and assessed using thermodynamic models for the Gibbs energies of individual phases. The ternary liquid and (Ni) phases are described with a regular solution model. The two-sublattice model is used to model the binary phases NbCr2(HT), NbCr2(LT), NbNi3, and Nb6Ni7. In order to reproduce the measured solid solubilities in the ternary system and to reduce the number of adjustable parameters, the third element is assumed to be anti-site atoms in only one sublattice. Optimal thermodynamic parameters are obtained by considering reliable literature data. Comprehensive comparisons between calculated and measured phase diagrams show that all the accurate experimental information is satisfactorily accounted for by the present thermodynamic description. The thermodynamic parameters obtained can also describe the diffusion paths observed for the diffusion couples between Nb and several Cr-Ni alloys annealed at 1002℃

The thermodynamic database for the Al-Fe-Mg-Mn-Si system is developed based on the constituent binary, ternary, and quarternary systems. The computed phase diagrams agree well with the experimental data. The obtained database is used to describe the solidification behavior of Al 356.1 (91.95Al-0.46Fe-0.3Mg-0.32Mn-6.97Si, in wt.%) and Al 356.2 (92.77Al-0.08Fe-0.35Mg-6.8Si, in wt.%) under equilibrium and Gulliver-Scheil non-equilibrium conditions. The reliability of the established thermodynamic database is also verified by the good agreement between calculation and experiment for both equilibrium and Gulliver-Scheil non-equilibrium solidifications. Microstructure and microsegregation of the directionally solidified Al 356.1 alloy are investigated with a growth rate of 0.04445 cm s-1 and a temperature gradient of 45K cm-1. Fractions of solids formed are measured by using quantitative image analysis of back-scattered electron, and solute redistribution in the primary (Al) is determined by means of an area scan approach with a total of 2400 electron probe microanalysis point counts. A micromodel, which includes solid-state diffusion, secondary dendrite arm coarsening, and dendrite tip and eutectic undercooling, is coupled with a multicomponent phase diagram calculation engine (PanEngine) to predict the microstructure and microsegregation of the solidified alloy. Quantitative agreement of the model prediction with the experiment is obtained for concentration distributions in the primary (Al), the types and amounts of phases formed, and the solidification path.

The Al-Be system is investigated via three steps. In the first step, all of the experimentally measured phase diagram and thermodynamic data available in the literature are critically reviewed. On the basis of the assessed phase diagram, in the second step, eight decisive samples are prepared by arc melting of Al and Be pieces and annealing at 600℃ for eight days. Water-quenched samples are analyzed using differential thermal analysis (DTA), X-ray diffraction (XRD), optical microscopy, and scanning electron microscopy (SEM) techniques. In the last step, an optimal thermodynamic data set for the Al-Be system has been obtained by considering the present experimental data and the reliable literature data. The calculated phase diagram and thermodynamic properties agree well with the accurate experimental values.

Thermodynamic optimizations of the Mo-Nb, Mo-Ta, and Nb-Ta binary systems were performed by considering the experimental phase diagram and thermodynamic data available from the literature. The Mo-Nb-Ta ternary system was then synthesized from the descriptions of the binary sides. The calculated thermodynamic properties as well as phase diagrams for the binary systems agree well with the experimental ones. In the case of the ternary system, several isothermal sections were calculated by extrapolation from the three boundary systems. The model-predicted liquidus temperatures in the ternary system are in reasonable agreement with the experimental data. The computed liquidus projection and a set of model parameters describing the Gibbs energies of the assessed phases are also presented.