Determination of viscosity and surface tension of liquid Ni–Al–Ti system using the evaluated thermodynamic properties by AMCT

The thermophysical properties of Ni–Al. Ni–Ti, and Al–Ti alloys, i.e., viscosity and surface tension, have been investigated using the evaluated thermodynamic properties, i.e., enthalpy of mixing $$ \Delta H_{\text{mix}} $$, Gibbs free energy of mixing $$ \Delta G_{\text{mix}} $$, and excess Gibbs free energy $$ \Delta G_{{}}^{\text{E}} $$, by the atom and molecular coexistence theory. Then, the third-degree Redlich–Kister (R–K) parameters for viscosity, surface tension, and excess Gibbs free energy at 1973 K were obtained. Based on this, the isothermal viscosity of Ni–Al–Ti ternary melts was simultaneously determined form the excess viscosity of the above-mentioned three binary systems by CALPHAD model and the similarity coefficients by Chou’s model, and the surface tension of the liquid ternary Ni–Al–Ti alloy systems was investigated with considering the excess surface tension of the three binary systems by Chou’s model as well as the excess Gibbs free energy of Ni–Al–Ti melts by Butler’s model for the multicomponent system at 1973 K. The results showed that the viscosity and surface tension of liquid Ni–Al–Ti alloy increase with the increase in Ti content at a fixed Al/Ni ratio, whereas decreases with increasing Al/Ni ratio at a given alloy composition at 1973 K.