Estimation of Two Component Activities of Binary Liquid Alloys by the Pair Potential Energy Containing a Polynomial of the Partial Radial Distribution Function

Abstract

An investigation of partial radial distribution functions and atomic pair potentials within a system has established that the existing potential functions are rooted in the assumption of a static arrangement of atoms, overlooking their distribution and vibration. In this study, Hill’s proposed radial distribution function polynomials are applied for the pure gaseous state to a binary liquid alloy system to derive the pair potential energy. The partial radial distribution functions of 36 binary liquid alloy systems from the literature were used to bring in four thermodynamic models for validation. Results show that the molecular interaction volume model (MIVM) and regular solution model (RSM) outperform other models when an asymmetric method is used to calculate the partial radial distribution function. The MIVM exhibits an average SD of 0.095 and an average ARD of 32.2%. Similarly, the RSM demonstrates an average SD of 0.078 and an ARD of 32.2%. The Wilson model yields an average SD of 0.124 and an average ARD of 226%. The nonrandom two-liquid (NRTL) model exhibits an average SD of 0.225 and an average ARD of 911%. On applying the partial radial distribution function symmetry method, the MIVM and RSM outperform the other models, with an average SD of 0.143 and an average ARD of 165.9% for the MIVM. The RSM yields an average SD of 0.117 and an average ARD of 208.3%. The Wilson model exhibits the average values of 0.133 and 305.6% for SD and ARD, respectively. The NRTL model shows an average SD of 0.200 and an average ARD of 771.8%. Based on this result, the influence of the symmetry degree on the thermodynamic model is explored by examining the symmetry degree as defined by the experimental activity curves of the two components.