The early investigations on the Ruthenium-Tin system were carried out by Shwomma et al [1] who drew a diagram containing three intermediate phases: Ru2Sn3, Ru2Sn and Ru3Sn7. Ru2Sn3 formed by the peritectoid reaction Ru2Sn3 <-> (Ru) +RuSn2 at T=1373±10K, Ru3Sn7 is a congruently melting compound (Temperature not determined), RuSn2 formed by the peritectic reaction Ru2Sn<-> liq+Ru3Sn7 (T unknown), decomposed by eutectoid transformation RuSn2 <-> Ru2Sn3 +Ru3Sn7 at T=973K. The same authors have reported the crystal structures of all the intermetallic compounds. Later, Susz [2] confirmed the occurrence of only two intermetallic compounds: Ru3Sn7, melting congruently at T=1548±2K, and Ru2Sn3 with a peritectoid decomposition Ru2Sn3<-> (Ru) + Ru3Sn7 at T=1513±5 K. Susz [2] found two eutectics: Liquid <-> (Sn) + Ru3Sn7 at T=493K and Liquid <-> Ru3Sn7 + (Ru) at 1531±5K. The maximum solubility of Sn in Ru at T = 1639K, xSn = 0.02. Massalski et al. [3] preferred the diagram proposed by Shwomma et al [1]. In 1996, Perring et al. [4] have completely revised the Ru-Sn phase diagram by differential thermal analysis (DTA), X-ray diffraction, and microprobe measurements. The authors confirm the existence of the two phases Ru2Sn3 and Ru3Sn7: Ru2Sn3 decomposed by peritectic reaction at T = 1539±4 K and Ru3Sn7 has a congruent melting at T=1530±2K. Kawabata et al. [5] examined the liquidus boundaries by thermal analysis, segregation method and solid state emf measurements (using calcia stabilized zirconia solid electrolyte). Charles et al. [6] attempted to assess the phase diagram using the software NancyUn elaborated by Charles et al. [7]. This routine is less powerful than the Thermocalc software [8] because it took into account only the liquid and the terminal solid solutions (Ru) and (Sn) were not modeled. Using the spot technique, Ananthasivan et al. [9] measured the liquidus of Ru-Sn system in the composition range from 35 to 100 at.% Sn. Both Ru2Sn3 and Ru3Sn7 were reported to decompose peritectically, i.e. liquid + Ru<-> Ru2Sn3, liquid + Ru2Sn3<-> Ru3Sn7. A monotectic invariant reaction, i.e. liquid 1 <-> Ru + liquid 2, was detected at 1297±7 K and 37 at.%Sn. Recently, Long et al. [10] established a thermodynamic optimization of the Ru-Sn binary system with the Thermo-Calc software [8], In the assessment by [10] Copyright!©!2017,!!!!!!!!!!!!!!!!!!!!!!!!!!!! University!of!Mohammed!Premier!!!!!! Oujda!Morocco! New thermodynamic assessment of the Ruthenium-Tin system

Zirconium and its alloys are widely used in the nuclear industry. Under normal conditions, Zr-alloys are polycrystalline and contain a high density of grain and interphase boundaries. These boundaries function as paths for accelerated matter movement. The movement of fast diffusing elements (Co, Fe, Cr, Ni) in Zr alloys along boundaries produces technologically important changes in the materials in nuclear reactors at normal temperatures (similar to 550 K) e.g.: segregation, phase precipitation, hydrogen absorption, etc.In this work, diffusion parameters for fast diffusion in Zr at low temperature were assessed for Co and Cr. An improved database for DICTRA (DIffusion-Controlled-TRAnsformation) software for fast diffusion was obtained. The diffusion parameters in grain boundaries of alpha-Zr for Cr and Co were used from a particular kinetic diffusion model [1]. Simulated profiles were compared with previous experimental work [2]. The results of the comparison and the adequacy of the improved database are discussed.Diffusion profiles on grain boundaries in alpha-Zr for Cr and Co are presented in the temperature range of 380-460 K. (C) 2015 Elsevier B.V. All rights reserved.

The thermodynamic modelling of the Iron+Holmium binary system was carried out with the help of the CALPHAD (CALculation of PHAse Diagram) method. The four intermediate phases Fe17Ho2, Fe23Ho6, Fe3Ho and Fe2Ho have been treated as stoichiometric compounds while a solution model has been used for the description of the liquid phase and the (Fe) and (Ho) solid solutions. The excess term of the Gibbs free energy of the solution phases was assessed with the Redlich-Kister (Redlich and Kister, 1948) [1] polynomial equation. The calculations based on the thermodynamic modelling are in good agreement with the phase diagram data and experimental thermodynamic values available in the literature. (C) 2013 Elsevier Ltd. All rights reserved.

The holmium–nickel binary system has been thermodynamically assessed by means of the Thermo-Calc software. The Redlich–Kister (Ind Eng Chem 40:345–348, 1948) polynomial was used to describe the solid and liquid solution phases. Seven intermediate phases, Ho3Ni, Ho3Ni2, HoNi, HoNi3, Ho2Ni7, HoNi5, and Ho2Ni17 were treated as stoichiometric phases. The intermetallic compound HoNi2 in this binary system which has a homogeneity range was treated by a two-sublattice model (Sundman et al., Calphad 9:153–190, 1985; Hillert and Staffansson, Acta Chem Scand 24:3618–3626, 1970). The parameters of the Gibbs energy expressions were optimized according to all the available experimental information of both the equilibrium data and the thermodynamic results. The calculated phase diagram agrees very well with the experimental values from the literature.

The iron–lutetium and iron–thulium binary systems needed to be reassessed after the previous thermodynamic evaluation by Konar (2012) [1] because significant discrepancies were observed with the experimental data. Furthermore new thermodynamic data were published in the meantime. In the present work, the modelings were carried out with the help of the CALPHAD (CALculation of PHAse Diagram) method. The seven intermediate phases Fe23Lu6, Fe3Lu, Fe2Lu, Fe17Tm2, Fe23Tm6, Fe3Tm and Fe2Tm in these two binary systems have been treated as stoichiometric compounds while the Fe17Lu2 substoichiometric intermetallic compound in Lu, in the Fe–Lu binary system which has a homogeneity range, was treated by a two-sublattice model with convenient substitution in each sublattice (Sundman et al., 1985 [2]). A solution model has been used for the description of the liquid phase and the (Fe), (Lu) and (Tm) solid solutions. The excess term of the Gibbs energy of the solution phases was assessed with the Redlich–Kister (Redlich and Kister, 1948 [3]) polynomial equation. The calculations based on the thermodynamic modeling are in good agreement with the phase diagram data and experimental thermodynamic values available in the literature.

The phase diagrams and thermodynamic properties of RE-Pb (RE = Sc, Dy, Gd) systems have been assessed by means of the CALPHAD method. The solution phases (liquid, fcc, bcc and hcp) were described by the sublattice formalism and the excess term of the Gibbs energy with the Redlich-Kister equation. The stoichiometric intermetallic compounds (Sc5Pb3, Sc6Pb5, Dy5Pb4, DyPb, DyPb2, DyPb3, beta-Gd5Pb4, alpha-Gd5Pb4, Gd11Pb10, Gd6Pb7, GdPb2 and GdPb2) were modeled as line compounds. The non-stoichiometric Dy5Pb3 and Gd5Pb3 phases with a narrow homogeneity range were modeled using a two-sublattice model with substitution. A consistent set of the thermodynamic parameters leading to a reasonable agreement between the calculated results and literature data was obtained. (C) 2013 Elsevier B. V. All rights reserved.

The present study concerns the optimization of the Fe-Y and Ni-Sc systems by the help of the CALPHAD (CALculation of Phase Diagram) method, taking into account the available experimental results about phase equilibria and thermodynamic properties. The excess terms of the Gibbs energy of the solution phases (liquid, b.c.c., f.c.c. and h.c.p.) were assessed with the recent exponential temperature dependence of the interaction energies by Kaptay and compared with the linear dependence by Redlich-Kister. Furthermore, the computer program Thermo-Calc allows to obtain estimated data for experimentally undetermined thermodynamic properties and to compare the computed phase diagrams with those already published.

The thermodynamic modeling of the Iron-Yttrium binary system was carried out with the help of the CALPHAD (CALculation of PHAse Diagram) method. The excess term of the Gibbs energy of the solution phases (liquid, b.c.c., f.c.c. and h.c.p.) was assessed with the recent exponential temperature dependence of the interaction energies by Kaptay [1-3] and compared with the linear temperature dependence of Redlich-Kister [4] polynomial equation results. The intermetallic compounds Fe23Y6 and Fe2Y in this binary system which have a homogeneity range, were treated by a two-sublattice model with convenient substitution in each sublattice [5,6]. The others were considered as stoichiometric compounds. A consistent set of thermodynamic parameters leading to a reasonable agreement between the calculated results and literature data was obtained for this system which has not been previously optimized. (C) 2013 Published by Elsevier B. V.

The thermodynamic modeling of the gallium–yttrium binary system was carried out with the help of the CALPHAD (CALculation of PHAse Diagram) method. Ga2Y, GaY, and the three polytypes Ga3Y5 have been treated as stoichiometric compounds while a solution model has been used for the description of the liquid phase and the (Ga) and (Y) solid solutions. The excess term of the Gibbs energy of the solution phases was assessed with the recent exponential temperature dependence of the interaction energies by Kaptay (Calphad 28–2:115–24, 1; Calphad 32–2:338–52, 2; Mat Sci Eng A 495:19–26, 3) and compared with the Redlich–Kister (Ind Eng Chem. 4;40:345) polynomial equation results. The calculations based on the thermodynamic modeling are in good agreement with the phase diagram data and experimental thermodynamic values available in the literature.

The Ni–Sc system was thermodynamically assessed by the CALPHAD approach based on the available experimental data including the thermodynamic properties and phase equilibria. The excess term of the Gibbs energy of the solution phases (liquid, b.c.c., f.c.c. and h.c.p.) was assessed with the recent exponential temperature dependence of the interaction energies by Kaptay (Calphad 28–2 (2004) 115–124; Calphad 32–2 (2008) 338–352; Mat. Sci. Eng. A 495 (2008) 19–26) and compared with Redlich and Kister (Ind. Eng. Chem. 40 (1948) 345–348) polynomial equation results. The intermetallic compound Ni2Sc in this binary system which has a homogeneity range, was treated by a two-sublattice model (Sundman et al., Calphad 9 (1985) 153–190; Hillert and Staffansson, Acta Chem. Scand 24 (1970) 3618). The others compounds were modeled as stoichiometric. A consistent set of thermodynamic parameters was optimized to give account of the available experimental and thermodynamic data.

The thermodynamic modeling of the silicon–tantalum binary system was carried out with the help of the CALPHAD (CALculation of PHAse Diagram) method. A solution model was used for the description of the liquid and bcc phases while the Si2Ta, Si3Ta5_LT, Si3Ta5_HT SiTa2 and SiTa3 compounds are treated as stoichiometric. The excess Gibbs energy function of the solution phases was assessed with the recent exponential temperature dependence of the interaction parameters by Kaptay [1] , [2] , [3] and compared with the Redlich–Kister [4] polynomial equation results. The calculations based on the thermodynamic modeling are in good agreement with the phase diagram data and experimental thermodynamic values available in literature.

We have analyzed the phase relationships in two titanium aluminides containing 3.4 at. % Mo with different aluminum compositions. The alloys were first homogenized in the β field, then cooled continuously at different cooling rates from 80 °C/s to 0.1 °C/s. The continuous cooling transformation diagrams (CCT) show that phase transformations and resulting microstructures are highly dependent on cooling rate. The microstructure consists of ordered α2 (DO19), ordered β0 (B2), and athermal ω (hexagonal) phases. The “tweed microstructure” is observed. The evolution of microhardness was determined as well as the relative partitioning of Al and Mo in (α2', α2) and β0 phases as a function of cooling rate.

Optical metallography, scanning electron microscopy, electron microprobe analysis, and transmission electron microscopy were used to characterize metallurgical grade silicon, produced in an electric are furnace. Coincidence fraction determinations were assumed to be Σ7 and Σ9 when grain boundaries are underlined by precipitated phases and Σ3 when they are not. The study of intergranular compounds was emphasized; ten compounds were found, the main ones being Si2Ca, Si8Al6Fe4Ca, Si2Al2Ca, Si2FeTi, and Si2.4Fe (α leboitc). The precipitation of these compounds was discussed according to the principal impurity concentrations in silicon. The crystalline structure of Si8Al6Fe4Ca was determined to be triclinic with a = 1.3923 nm, b = 1.3896 nm, c = 1.3900 nm and α = 92.4°, β = 110.3°, γ = 119.9°.

The aging of the NC 19 Fe Nb alloy (Inconel 718), previously quenched from 990 °C, is characterized by a hardness peak at 650 °C, then a maximum in hardness at about 750 °C. Over this temperature, the hardness progressively decreases. In the 550–650 ° C temperature range, TEM observations have revealed that ß (Ni_3Nb) precipitates are formed as long platelets parallel between them within the same grain, as well as extremely fine γ′[Ni_3(Ti, Al)] particles responsible for the observed improvement in hardness. For a tempering temperature higher than 650 °C, a first hardening occurs after a 4 h treatment, which has been associated with the γ ′ phase precipitation, with a more or less spherical shape. Beyond this time, a second hardening takes place linked to the γ ″ phase precipitation (Ni_3Nb, bct D0_22 structure), as thin platelet shaped, perfectly coherent with the matrix. The misfit between the γ and γ ″ phases is about 3% in the 〈001〉 γ ″ direction and lower than 1% in the 〈100〉 γ ″ and 〈010〉 γ ″ directions. During a longer aging at 750 °C, the γ ″ platelets progressively dissolve while ß precipitates grow.

Until now, no thermodynamic calculation has been done for the Ga-La system In the present work, it has been evaluated by means of the Calphad approach The solution phases (Liquid, (αLa), (βLa) and (γLa)) were modelled with the sublattice formalism and the excess term of the Gibbs energy with the Redlich-Kister equation. The intermetallic compound Ga2La which has a homogeneity range, was treated as the formula (Ga)0.667 (Ga,La)0.333 by a two-sublattice model with Ga on the first sublattice and Ga and La on the second one. Ga 6 La, Ga 4 La, GaLa, Ga 3 La 5 , GaLa 3 have been treated as stoichiometric compounds. The calculated phase diagram and the thermodynamic properties of the system are in satisfactory agreement with the experimental data.

The copper rich corner of the CuNiSn system is frequently studied for the high tensile strength and good electrical conductivity of the alloys. In this study, we focus on the phase transformations at high temperature. The incipient melting is studied in some detail just below 1000 °C since the presence of an unexpected peak at 985 °C on the DTA’s thermograms is detected.

A new numerical tool has been developed by coupling the diffusion code "EKINOX" (Estimation Kinetics Oxidation) and the thermodynamic database "ZIRCOBASE" using TQ(ThermoCalc program interface). The aim of this tool is to calculate the oxygen diffusion during oxidation of Zr based alloys. The simulation results of the oxide growth kinetics and the induced oxygen diffusion profiles in the [1100-1250 degrees C] temperature range, at different times, are presented and compared to previous experimental results. An estimation of the diffusion coefficient in the alpha phase is deduced from this comparison. The results are discussed in comparison to previous models based on an analytical treatment and the influence of the choice of the thermodynamic data set on the final oxygen diffusion profile is explored.Finally, it is shown that the present modeling is able to predict quite accurately the "critical" oxidation time corresponding to the overall ductile-to-brittle transition of the high temperature (HT) oxidized clad. (C) 2010 Elsevier B.V. All rights reserved.

Thermodynamic modelling of the Pb–Yb binary system was carried out with the help of the CALPHAD method. The liquid phase has been described with the association solution model with ‘ Pb1Y b2’ as an associated complex. The solution phases BCC_A2 and FCC_A1 were modelled with the sublattice formalism. The αPbYb_LT and βPbYb_HT Pb sub-stoichiometric intermetallic compounds, which have a homogeneity range, were treated with the formula (Pb,Y b)0.5(Y b)0.5 by a two-sublattice model with Pb and Yb on the first sublattice and Yb on the second one. Pb3Y b, Pb3Y b5 and PbY b2 have been treated as stoichiometric compounds. The calculations based on the thermodynamic modelling are in good agreement with the phase diagram data and experimental thermodynamic values.

The thermodynamic modelling of the La-Pb binary system was carried out with the help of CALPHAD (CALculation of PHAse Diagram) method. La5Pb3, La4Pb3, La5Pb4, αLa3Pb4, βLa3Pb4, LaPb2, LaPb3 have been treated as stoichiometric compounds while a solution model has been used for the description of the liquid, BCC and FCC phases. The calculations based on the thermodynamic modeling are in good agreement with the phase diagram data and experimental thermodynamic values.

The Zircobase thermodynamic database for zirconium alloys coupled with Thermo-Calc software represents a powerful tool for prediction of thermodynamic and metallurgical data such as activities, formation enthalpies, phase transformation temperatures, solubility limits, existence temperature range, and chemical compositions of second phase precipitates. This database was built up with binary and ternary descriptions assessed according to the CALPHAD methodology. It is sometimes necessary to take into account new systems, but also new versions of binary descriptions as recently experienced. For example, the two binary systems Zr-Fe and Zr-Sn had to be updated in order to fit new experimental results believed to be more accurate than previously available. This paper aims at showing the improvements of the database taking into account new descriptions of binary systems, as also ternary description such as Zr-Fe-Cr, Zr-Fe-Ni, and Zr-Nb-Fe. For this last ternary system, new experimental data were necessary. New experimental study of the two ternary phases, hexagonal Zr(Nb,Fe)2 and cubic (Zr,Nb)4Fe2, allowed their crystal structures (P63/mmc and Fd3¯ m, respectively) to be checked. This was useful to build up a sublattice model giving account of the existence of a composition range for these two intermetallic phases. Moreover, several specific ZrNbFe alloys were fabricated and annealed for times ranging from 1000 h to 10,000 h at 550, 700, 800, and 900°C to determine the equilibrium binary and ternary phase domains as a function of the temperature. All these data were used to obtain an improved thermodynamic modelling of this system. Finally, we illustrate some thermodynamic predictions of the different phases evolutions as a function of the temperature on multi-alloyed industrial type alloys. These examples show quite good agreement between the thermodynamic predictions and the experimental data derived from calorimetric experiments and microstructural observations.