The Gibbs adsorption isotherm and Wagner’s definition of excess solute at surfaces and grain boundaries were extended so as to include other crystalline defects such as dislocations and vacancies. By using a thermodynamic state function which was suitable for a partially open system (open with respect to solvent and closed with respect to solute atoms), a generalized Gibbs adsorption isotherm could be derived. Thus, solute segregation to dislocations and vacancies also gave rise to a reduction in their formation energies. The results of the treatment were compared with the results of statistical mechanics and computer simulation techniques. Particular attention was paid to whether defect energies could become zero or negative.

Reducing Grain Boundary, Dislocation Line and Vacancy Formation Energies by Solute Segregation I - Theoretical Background. R.Kirchheim: Acta Materialia, 2007, 55[15], 5129-38