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MM: Fachverband Metall- und Materialphysik

MM 36: Topical Session Electron Theory V

MM 36.3: Talk

Thursday, March 17, 2011, 15:00–15:15, IFW A

Thermodynamic model of alloy grain boundaries — •Alexander Kirchner — Institut für Werkstoffwissenschaft, Technische Universität, 01062 Dresden, Germany

A facile thermodynamic model for grain boundaries in substitutional alloys is developed. The macroscopic analysis is based on established descriptions of metallic solutions and the universal equation of state at negative pressure. The thermodynamic potential free energy of atoms in grain boundaries is derived as a function of excess volume and composition. Employing Guggenheim's condition for equilibrium between bulk phase and grain boundaries, the interface free energy and segregation enrichment are expressed. For binary systems with known segregation behavior these quantities are calculated. The results show good agreement with experimental data. Despite inherent limitation which are discussed the proposed model is especially useful for the understanding of nanocrystalline materials.