Thermodynamic model of alloy grain boundaries

A facile thermodynamic model for grain boundaries in dilute alloys is developed. The macroscopic analysis is based on known descriptions of metallic solutions and the universal equation of state. The thermodynamic variable free energy is derived as a function of composition and excess volume. Employing Guggenheim’s condition for equilibrium between bulk and grain boundaries, the segregation behavior and the interface free energy of two model systems, copper–silver and copper–bismuth, are calculated. The results show good agreement with experimental data.