Surface Tension of GaInSnBiZn Liquid High-entropy Alloy

As an emerging alloy material, high-entropy alloy has potential applications that distinguish it from traditional alloys due to its special physicochemical properties. In this work, a low melting point GaInSnBiZn high-entropy alloy was designed based on Miedema model, and its surface tension was measured by the continuous pendant-drop method. The results show that the intrinsic surface tension of GaInSnBiZn high-entropy alloy at 80 °C is 545±5 mN/m, and the surface tension of the liquid alloy is significantly reduced by the formation of surface oxide film. The surface tension of GaInSnBiZn high-entropy alloy was analyzed by using theoretical models (Guggenheim model, GSM (general solution) model and Butler model), and the thermodynamic characteristics of the surface tension formation were further verified by combining with thermodynamic calculations, among which the calculated results of Butler model were in good agreement with the experimental data. Meanwhile, it is found that the surface concentration of Bi in the alloy is much larger than the nominal concentration of its bulk phase, which contributes the most to the surface tension of the alloy, however, it contributes the least to the entropy of the alloy formation in combination with the Butler model.

Ternary Bi-Cu-Ni alloys – thermodynamics, characterization, mechanical and electrical properties

The Bi–Cu–Ni ternary system belongs to the group of potential Cu-Ni-based advanced lead-free solder materials for high temperature application. The paper shows results of the thermodynamic calculations using general solution model along the line with the molar ratio of Cu: Ni = 1:1. The experimental part shows thermal, structural, electrical and mechanical properties based on differential scanning calorimetry (DSC), scanning electron microscopy with energy dispersive spectrometry (SEM-EDS), electroconductivity and hardness measurements of the alloys selected in the section from bismuth corner with molar ratio Cu: Ni = 1:1, Cu: Ni = 3:1, and Cu: Ni = 1:3.

Estimation of viscosity for some silicate ternary slags

A new method, combining KTH model with geometrical model (General solution model by Chou) to estimate viscosity of some ternary silicate slags, was proposed in this work. According to modified KTH model, viscous Gibbs free energy for mixing of ternary slags was estimated by employing general solution model. It was found that viscous Gibbs energy for mixing of ternary system could be calculated using solely viscous Gibbs energy for mixing of sub-binary systems. The viscosities of five ternary slags CaO-MnO-SiO2, CaO-FeO-SiO2, FeO-MnO-SiO2, CaO-MgO-SiO2 and FeO-MgO-SiO2 were estimated in the present work. A good agreement with available experimental data, with mean deviation less than 20%, was achieved. The modified KTH model has advantages with less model parameters and improved estimation ability by comparison to original KTH model.

Cu-Al-Zn system: Calculation of thermodynamic properties in liquid phase

In the paper are presented the results of thermodynamic analysis of Cu-Al-Zn ternary system, which belongs to a group of copper-based shape memory materials. General solution model was used for calculation of thermodynamic properties in the temperature interval from 1373 to 2173 K, in sections from Cu, Al and Zn corner, respectively, with following ratios of 1:3, 1:1 and 3:1. Also, on the basis of the obtained results, ternary interaction parameters were determined using Mathematical Modeling System (MLAB).

Thermodynamic description of the Cu-Ni-Pb system

Thermodynamic description is presented for the ternary Cu-Ni-Pb system. Optimized parameters of the sub-systems, Cu-Ni, Cu-Pb and Ni-Pb, are taken from earlier assessments and those of the ternary system are optimized in this study by using the experimental phase equilibrium and thermodynamic data. Better agreement is obtained by the present optimization. Calculated results are compared with the original experimental data to demonstrate the successfulness of this assessment. Moreover, a geometric model (general solution model) is used to estimate ternary integral molar Gibbs excess energies of the liquid phase from the bibary systems only. These values, however, disagree with the quantities obtained by thermodynamic optimizations.

Sn-Ni-Bi liquid phase thermodynamic properties

Experimental data of bismuth activity coefficients at 1773 K were obtained by isopiestic method and compared to calculated values. Thermodynamic properties of the Sn-Ni-Bi liquid phase were estimated by means of the general solution model and by the methods of Kohler. Description of the ternary liquid phase (Gibbs excess energy dependence on the temperature and the composition) was achieved by using available thermodynamic data of the constitutive binary systems (Ni-Bi, Sn-Bi, Sn-Ni). A comparison between calculated quantities and experimental data wasconducted. The present assessment with thermodynamically optimized values of the system Sn-Ni-Bi (obtained by the CALPHAD approach) was in good agreement. The suggested appearance of a liquid phase miscibility gap at high temperatures is in agreement with the experimental bismuth activity data and with the assessed thermochemical functions.