Experimental Investigation of Phase Equilibria in the Fe-Si-Ti Ternary System

The phase equilibria of the Fe-Si-Ti ternary system were investigated by electron probe microanalyzer (EPMA), back scattered electron (BSE) and X-ray diffraction (XRD) on the equilibrated alloys. Twenty-four alloys of the Fe-Si-Ti ternary system were prepared. In this study, three isothermal sections of the Fe-Si-Ti ternary system at 1000, 1100 and 1200 °C were respectively determined and seven ternary compounds were confirmed. The ηFe₅Si₃ phase is discovered at 1100 and disappeared at 1200 °C. The obtained experimental results show that there is large solubilities of Si in the TiFe₂ phase. The newly determined phase equilibria of the Fe-Si-Ti system will provide useful information for the development of silicon steels.     

Experimental Investigation and Thermodynamic Calculation of Phase Equilibria in the Mg-Pb-Sn Ternary System

The phase equilibria of the Mg-Pb-Sn ternary system were investigated using a combined method of electron probe microanalyzer and x-ray diffraction. Three isothermal sections of the Mg-Pb-Sn ternary system at 200, 300 and 400 °C were experimentally established. The phase equilibria of Mg-Pb-Sn ternary system were thermodynamically assessed by using CALPHAD (Calculation of Phase Diagrams) method on the basis of the presently determined experimental data. A consistent set of thermodynamic parameters has been derived for describing the Gibbs free energies of each solution phase and intermetallic compound in the Mg-Pb-Sn ternary system. The calculated phase diagrams and thermodynamic properties in the Mg-Pb-Sn ternary system are in good agreement with experimental data.     

Experimental Investigation and Thermodynamic Calculation of the Phase Equilibria in the Al-Bi-Sn Ternary System

This work first deals with the experimental investigation and thermodynamic calculation in the Al-Bi-Sn ternary system. The phase equilibria at 400 and 500 °C in the Al-Bi-Sn ternary system have been experimentally determined by electron probe microanalysis (EPMA) on the equilibrated alloys. Based on the experimental data determined in the present work, the phase equilibria in the Al-Bi-Sn ternary system have been thermodynamically assessed by using the CALPHAD (CALculation of PHAse Diagrams) method, and a consistent set of thermodynamic parameters leading to reasonable agreement between the calculated results and experimental data was obtained. The additions of Sn can effectively reduce the stable liquid miscibility gap in the Al-Bi binary system and gradually decrease its critical temperature. And the additions of Bi can significantly stabilize the metastable liquid miscibility gap in the Al-Sn binary system. This is shown by an initial decrease in critical temperature with increasing Bi additions.     

Experimental Investigation and Thermodynamic Calculation of the Phase Equilibria in the Co-Cu-V Ternary System

The phase equilibria of the Co-Cu-V ternary system at 900, 1000, 1100 and 1200 °C have been experimentally determined by optical microscopy and electron probe micro-analysis of the equilibrated alloys. The phase transformations were investigated by means of the differential scanning calorimetry. Based on the experimental data of phase equilibria and thermodynamic properties, the thermodynamic assessment of the Co-Cu-V ternary system was carried out by using the calculation of phase diagrams method. A consistent set of the thermodynamic parameters leading to reasonable agreement between the calculated results and experimental data was obtained in the Co-Cu-V ternary system. Meanwhile, the calculated results show that the critical temperature of metastable magnetically induced miscibility gap of (α _f Co) and (α _p Co) phases in the Co-V system gradually decreases with increasing Cu composition in the range of 0-3 wt.% additions.     

Experimental Investigation of Phase Equilibria in the Fe-Nb-Ta System

The phase equilibria in the Fe-Nb-Ta ternary system at 1200, 1100 and 1000 °C were experimentally investigated. The microstructure of each sample was observed using scanning electron microscopy, and phase compositions were measured by energy dispersive spectrometry. The constituent phases of typical samples were analyzed with x-ray diffraction. The experimental results indicated that the continuous solid solution phases, Fe₂(Nb,Ta) and Fe₇(Nb,Ta)₆, were formed between Fe₂Nb and Fe₂Ta and Fe₇Nb₆ and Fe₇Ta₆, respectively, and no ternary compounds were found in this system in these isothermal sections. Based on the experimental phase equilibria data obtained in the present work, three isothermal sections at 1200, 1100 and 1000 °C were constructed.     

Experimental Investigation and Thermodynamic Calculation of the Phase Equilibria in the Bi-Cu-Zn Ternary System

The phase equilibria of the Bi-Cu-Zn ternary system has been firstly and comprehensively investigated by electron probe microanalyzer (EPMA) with equilibrated alloys. Two isothermal sections of the Bi-Cu-Zn ternary system at 500 and 650 °C were determined. Based on the experimental data of phase equilibria, the Bi-Cu-Zn ternary system was also thermodynamically optimized using the Calculation of Phase Diagrams (CALPHAD) method. The experimental result shows that Bi is almost insoluble in the Cu-Zn binary compounds and (Cu) phase. It is found that the critical temperatures of the miscibility gaps in the Bi-Cu and Bi-Zn binary systems gradually increase with the increasing of the third element Zn or Cu additions. Moreover, the composition range of the liquid miscibility gap gradually reduces with the temperature increasing.     

Experimental Determination of Phase Equilibria in the Co-Cr-V Ternary System

The phase equilibria in the Co-Cr-V ternary system were investigated by means of optical microscopy, electron probe microanalysis and x-ray diffraction. Four isothermal sections of the Co-Cr-V ternary system at 800, 1000, 1100 and 1200?°C were established. The experimental results show that: (1) no ternary compound was found in this system; (2) the ?? and (V, Cr) phases form the continuous solid solutions from the Co-Cr side to Co-V side in the isothermal sections at 800-1200?°C.     

Phase Equilibria of the Cu-Sn-Bi Ternary System

Phase equilibria of the Cu-Sn-Bi ternary system have been investigated by means of x-ray diffraction, scanning electron microscopy and energy-dispersive spectrometry analysis. Cu-Sn-Bi alloys were prepared and equilibrated at 250, 450 and 700 °C, and the equilibrium phases were experimentally identified. Isothermal sections at these three temperatures were proposed based on the experimental results and the information on the three constituent binary systems. Moreover, the solubility of the Bi in the Cu-Sn compounds is less than 0.8 at%. No ternary compound was found. The phase equilibria between the liquid and the solid phases appears to be inclined towards the Bi-corner at all temperatures.     

Thermodynamic Optimization of the Ni-Al-Ce Ternary System

The Ni-Al-Ce ternary system has been thermodynamically optimized in order to be integrated into the database for Ni-base alloys containing rare earth elements. A comprehensive set of thermodynamic parameters including all the ternary intermetallic compounds have been obtained. The calculated enthalpies of formation for ternary compounds by the present work are consistent with values from other sources. Isothermal sections at 1073 and 773 K and liquidus projection have been calculated. Ternary phase equilibria have been well reproduced compared to experimental data.     

Assessment of thermodynamic properties and phase diagram in the Ag–In–Pd system

Phase equilibria in the Ag–In–Pd system were determined at 500 °C based on experimental results for 16 alloys. A ternary intermetallic compound (T₁) in the palladium-rich region was confirmed by X-ray diffractometry. The experimental data were first compared with the results of a CALPHAD-type prediction, based on binary thermodynamic data using only a symmetrical Redlich–Kister–Muggianu model. In a second step, the thermodynamic modeling of the different phases in this ternary system was refined by including ternary interactions, and the phase diagram was calculated for the temperature range between 500 and 700 °C. With the optimized thermodynamic parameters the phase diagram was extrapolated to 200 °C and compared with preliminary experimental results.     

Phase equilibria of the Sn–Ag–Ni ternary system and interfacial reactions at the Sn–Ag/Ni joints

There are no previous phase equilibria studies of the Sn–Ag–Ni ternary system, even though the phase equilibria information is important for the electronic industry. The isothermal section of the Sn–Ag–Ni ternary system at 240 °C has been determined in this study both by experimental examination and thermodynamic calculation. Experimental results show no existence of ternary compounds in the Sn–Ag–Ni system, and all the constituent binary compounds have very limited solubilities of the ternary elements. The binary Ni₃Sn₂ phase is very stable and is in equilibrium with most of the phases, Ag₃Sn, ζ-Ag₄Sn, Ag, Ni₃Sn₄ and Ni₃Sn phases. A preliminary thermodynamic model of the ternary system is developed based on the models of the three binary constituent systems without introducing any ternary interaction parameters. This ternary thermodynamic model is used with a commercial software Pandat to calculate the Sn–Ag–Ni 240 °C isothermal section. The phase relationships determined by calculation are consistent with those determined experimentally. Besides phase equilibria determination, the interfacial reactions between the Sn–Ag alloys with Ni substrate are investigated at 240, 300 and 400 °C, respectively. It is found that the phase formations in the Sn–3.5wt%Ag/Ni couples are very similar to those in the Sn/Ni couples.     

Phase equilibria in the Fe–Rh–Ti system II. CVM calculations

Cluster Variation Method (CVM) calculations of phase equilibria in the bcc Fe–Rh–Ti system were performed in the irregular tetrahedron (IT) approximation including tetrahedron interactions. The energy parameters were obtained from a fit to recent experimental data on phase equilibria at 1000 °C and 800 °C. At these temperatures the ordering between first nearest neighbours dominates leading to large single-phase fields with B2 ordering. At lower temperatures the calculations predict additional ordering between second nearest neighbours of type D0₃. In the Fe–Ti system the second neighbour interactions are of segregation type leading to miscibility gaps between the disordered A2 and the ordered B2 phases extending from the binary Fe–Ti system into the ternary system. Calculated isothermal sections are presented at several temperatures. The complex ordering in the ternary system leads to strong variations of chemical potentials with composition. This is shown by calculated iso-chemical potential contours.     

Experimental Investigation of Phase Equilibria in the Cu-Fe-Zr Ternary System

The phase equilibria in the Cu-Fe-Zr ternary system was experimentally investigated by optical microscopy, electron probe micro-analyzer and x-ray diffraction on the equilibriated alloys. Three isothermal sections of the Cu-Fe-Zr ternary system at 1000, 1100 and 1200 °C were experimentally determined, and no ternary compound was found in this system. The further result in the present work shows that the Fe₂₃Zr₆ phase in the Cu-Fe-Zr ternary system is an equilibrium phase rather than oxygen-stabilized phase.     

The ternary Gd-Li-Mg system: Phase diagram study and computational evaluation

The binary Gd-Li and the ternary Gd-Li-Mg systems were studied experimentally by thermal analysis and phase equilibration and also by thermodynamic calculations using the CALPHAD method. Ternary phase equilibria at 250 °C were studied with 55 different alloys that were annealed for 400 h and analyzed by x-ray diffractometry. A thermodynamic assessment of the binary Gd-Li system was also performed and the calculated phase diagram is presented. In the Gd-Li-Mg system, ternary solubilities of Li in GdMg (up to 5 at.% Li), GdMg₂ (up to approximately 3 at.% Li), and GdMg₃ (up to 5 at.% Li) were found at 250 °C. No ternary compound was observed. Lattice parameters for different compositions are given for these phases. Thermal analysis using a ternary key sample of composition near the invariant reaction L′=L+(βGd)+GdMg provided the data that were needed to determine a thermodynamic parameter for the ternary liquid. Thermodynamic data sets for the ternary solid solution phases were also developed. Based on the present data sets and those of the binary Gd-Mg and Li-Mg systems from the literature, the phase equilibria in the entire ternary system were calculated. Isothermal and vertical sections of the phase diagram and the projection of the liquidus surface are shown. These calculated phase diagrams are well supported by the experimental data.