Equilibrium vacancy concentration and thermodynamic quantities of BCC defective alloys FeCrSi and VWSi under pressure

Abstract

In this paper, we present the analytic expressions of the cohesive energy, the alloy parameters, the equation of state, the mean nearest neighbor distance, the Helmholtz free energy, equilibrium vacancy concentration and thermodynamic quantities such as the isothermal compressibility, the thermal expansion coefficient, the heat capacities at constant volume and at constant pressure for BCC defective ternary substitutional and interstitial alloy ABC derived by the statistical moment method. The obtained thermodynamic quantities depend on temperature, pressure, concentration of substitutional atoms, concentration of interstitial atoms and equilibrium vacancy concentration. Thermodynamic quantities of BCC defective metal A, BCC defective substitutional alloy AB, BCC defective interstitial alloy AC and BCC defective metal A are specific cases for thermodynamic quantities of BCC defective ternary substitutional and interstitial alloy ABC. The theoretical results are calculated numerically to alloys FeCrSi and VWSi. Our calculated results of thermal expansion coefficient and heat capacities at constant pressure for main metals Fe, V are in good agreement with experimental data. Our other calculated results for thermodynamic quantities of alloys FeCrSi and VWSi at different temperature, pressure, concentration of substitutional atoms and concentration of interstitial atoms orient and predict new experimental data in the future