Ali Dogan

An analytical approach for thermodynamic properties of the six-component systems Ni-Cr-Co-Al-Mo-Ti and their subsystems

In the present study, the results of some thermodynamic prediction methods were applied to the Ni-Cr-Co-Al-Mo-Ti system of six components. The Chou’s general solution model and the traditional models of Kohler and Muggianu were included in the calculation for the comparison and discussion. The excess Gibbs energy dependences on composition for two investigated cross sections at 2000 K, were obtained according to the applied models. The comparison between the results of the three models shows good mutual agreement.

Estimation of excess energies and activity coefficients for the penternary Ni-Cr-Co-Al-Mo system and its subsystems

Using different prediction methods, such as the General Solution Model of Kohler and Muggianu, the excess energy and activities of molybdenum for the sections of the phase diagram for the penternary Ni-Cr-Co-Al-Mo system with mole ratios xNi/xMo = 1, xCr/xMo = 1, xCo/xMo = 1, and xAl/xMo = r = 0.5 and 1, were thermodynamically investigated at a temperature of 2000 K, whereas the excess energy and activities of Bi for the section corresponding to the ternary Bi-Ga-Sb system with mole ratio xGa/xSb = 1/9 were thermodynamically investigated at a temperature of 1073 K. In the case of r = 0.5 and 1 in the alloys Ni-Cr-Co-Al-Mo, a positive deviation in the activity coefficient was revealed, as molybdenum content increased. Moreover, in the calculations performed in Chou’s GSM model, the obtained values for excess Gibbs energies are negative in the whole concentration range of bismuth at 1073 K and exhibit the minimum of about −2.2 kJ/mol at the mole ratio xGa/xSb = 1/9 in the alloy Bi-Ga-Sb.

Geometric modelling of viscosity of copper-containing liquid alloys

Abstract In this work, viscosities of ternary Au–Ag–Cu and Al–Cu–Si liquid alloys have been calculated as a function of gold, aluminium and copper compositions for the sections Au–Ag–Cu (xAg/xCu = 0.543 at 1373 K), Alx(Cu50–Si50)(1–x) and Cux(Al50–Si50)(1–x) at 1375 K using Chou’s general solution model, Muggianu, Kohler, Toop, Hillert, Budai et al., Kozlov et al., Schick et al. and Kaptay et al. models. The present study finds that a comparison of the predicted values of viscosities associated with the geometric and physical models indicate good mutual agreement. The Muggianu model indicates the best agreement with the results obtained for Au–Ag–Cu and Alx–Cu50–Si50 alloy systems and the Kaptay et al. model, which is a physical model, indicates the best agreement with the results obtained for Al50–Cux–Si50.

An investigation on surface tensions of Pb-free solder materials

Abstract Surface tensions of some Pb-free solder systems such as Ag–Bi–Sn with cross-sections Ag/Bi = 1/1, Ag/Bi = 1/2, Ag/Bi = 2/1, In–Sn–Zn with cross-sections Sn/In = 1/1, Sn/In = 1/3 and (Ag7Cu3)100−x Snx with cross-section Ag/Cu = 7/3 are calculated from the sub-binary surface tension data using the models, such as the Muggianu, Kohler, Toop models, Butler’s equation and Chou’s General Solution Model (GSM) at 873, 923 and 1073 K, respectively. The surface tension of In–Sn–Zn increases wavily with increasing amount of Zn and it is found that the best models are the GSM for both cross-sections in question while GSM becomes the best model for (Ag7Cu3)100−x Snx alloy in the whole experimental range. Moreover, the surface tension of (Ag7Cu3)100−x Snx decreases slightly with increasing amount of Sn. The Muggianu, Butler and Butler models are determined as the best models for the cross-sections in the order given above for entire measurement range, respectively, and the surface tension of Ag–Bi–Sn decreases slightly with an increasing amount of Bi and Ag but increases with increasing Sn in liquid alloys.

Thermophysical properties of Cu–In–Sn liquid Pb-free alloys: viscosity and surface tension

Abstract The viscosity of a few Cu–In–Sn liquid alloys has been investigated by a number of geometric (Muggianu, Kohler, Toop) and physical thermodynamic models (Kozlov–Romanov–Petrov, Budai–Benko–Kaptay, Schick et al.) and GSM for the cross section (z/y = 1/3) in Pb-free liquid alloy Cux–Iny–Snz at 1073 K. Moreover, the surface tensions of the same liquid alloys have been investigated by a number of geometric models and the Butler model for the cross section Cux–Iny–Snz (z/(y + z) = 0, 0.1, 0.3, 0.5, 0.7, 0.9, 1) at the same temperature. The best agreement of the surface tensions was obtained in the Kohler model for xCu = 10 at % and the Butler model for xCu = 20 at % and xCu = 30 at.%, respectively. The best agreement among chosen geometric and physical models and experiment for these selected sections Cu80In15Sn5, Cu75In15Sn10, Cu55In7Sn38, Cu33In50Sn17 and Cu26In55Sn19 at 1073 K was obtained for the Budai–Benkö–Kaptay model.

Composition dependences of thermodynamical properties associated with Pb-free ternary, quaternary, and quinary solder systems

In the present study, Chou’s General Solution Model (GSM) has been used to predict the enthalpy and partial enthalpies of mixing of the liquid Ag–In–Sn ternary, Ag–In–Sn–Zn quaternary, and Ag–Au–In–Sn–Zn quinary systems. These are of technical importance to optimize lead-free solder alloys, in selected cross-sections: xIn/xSn = 0.5/0.5 (ternary), Au–In0.1–Sn0.8–Zn0.1, Ag–In0.1–Sn0.8–Zn0.1 (quaternary), and t = xAu/xIn = 1, xIn = xSn = xZn (quinary) at 1173, 773, and 773 K, respectively. Moreover, the activity of In content in the ternary alloy system Ag–In–Sn has been calculated and its result is compared with that determined from the experiment, while the activities of Ag contents associated with the alloys mentioned above have been calculated. The other traditional models such as of Colinet, Kohler, Muggianu, Toop, and Hillert are also included in calculations. Comparing those calculated from the proposed GSM with those determined from experimental measurements, it is seen that this model becomes considerably realistic in computerization for estimating thermodynamic properties in multicomponent systems.

Calculation of the surface tension of liquid Ga-based alloys

Abstract As known, Eyring and his collaborators have applied the structure theory to the properties of binary liquid mixtures. In this work, the Eyring model has been extended to calculate the surface tension of liquid Ga–Bi, Ga–Sn and Ga–In binary alloys. It was found that the addition of Sn, In and Bi into Ga leads to significant decrease in the surface tension of the three Ga-based alloy systems, especially for that of Ga–Bi alloys. The calculated surface tension values of these alloys exhibit negative deviation from the corresponding ideal mixing isotherms. Moreover, a comparison between the calculated results and corresponding literature data indicates a good agreement.

Theoretical calculation of surface tension and its temperature coefficient associated with liquid Cu–Ti alloys

ABSTRACT In this work, the surface tension of Cu–Ti binary liquid alloys is calculated in the framework of Eyring theory as a function of composition and temperature. It is observed that for all investigated alloys the surface tension can be described by a linear function of the temperature with negative slope, and the temperature coefficient of surface tension decreases as Ti-content of the alloys increases linearly. The obtained theoretical results are compared to the experimental data available in the literature as well as to the theoretical results evaluated by using four models, such as the compound formation model, the quasi-chemical approximation for regular solutions, ideal solution model and Butler model treated in literature frequently.

Surface tension estimation of high temperature melts of the binary alloys Ag–Au

Abstract Surface tension calculation of the binary alloys Ag–Au at the temperature of 1381 K, where Ag and Au have similar electronic structures and their atomic radii are comparable, are carried out in this study using several equations over entire composition range of Au. Apparently, the deviations from ideality of the bulk solutions, such as activities of Ag and Au are small and the maximum excess Gibbs free energy of mixing of the liquid phase is for instance −4500 J/mol at XAu = 0.5. Besides, the results obtained in Ag–Au alloys that at a constant temperature the surface tension increases with increasing composition while the surface tension decreases as the temperature increases for entire composition range of Au. Although data about surface tension of the Ag–Au alloy are limited, it was possible to make a comparison for the calculated results for the surface tension in this study with the available experimental data. Taken together, the average standard error analysis that especially the improved Guggenheim model in the other models gives the best agreement along with the experimental results at temperature 1383 K although almost all models are mutually in agreement with the other one.

Determination of crystallographic parameters associated with martensitic transformation in the alloy Fe-24.5 at % Pt

Considering the concrete slip system as a lattice invariant shear one, the orientation relationship between austenite and martensite and the analytical solutions for the habitus orientation, amount of lattice invariant deformation, and magnitude of the total shape deformation have been derived using rigorous version of the infinitesimal deformation (ID) approach for a description of the fcc to bcc martensitic transformation observed in an iron-platinum alloy with 24.5 at % Pt. The results of the present study are numerically compared with those obtained both in experiment and within the infinitesimal approach and a phenomenological theory of Bowles and Mackenzie (BM).