On impurity segregation on dislocations in metals

Thermodynamic and crystallo-chemistry considerations are given about the possibility of existing linear distribution laws for some impurities in metals between bulk solution and near-dislocation segregation regions (NDSR) with composition and structure close to the corresponding intermetallic compound. The solutions of Fe in Al are considered. NDSR composition can be close to FeAl3. The experimental data on the solubilities are treated within the model developed to determine the effective binding enthalpy which is close to the dissolution enthalpy of the FeAl3 compounds in Al. The effective distribution law differs from true adsorption forms. It is valid for limited concentration range and connected to the phase diagram change for the NDSR. The known diffraction anomalies for transition impurities in Al are satisfactory explained with using this distribution law. (orig.)