Fachbereich 11 - Physik
Institut für Materialphysik
Diffusion and Segregation in Grain and Interphase Boundaries

Solute diffusion and segregation in grain boundaries of copper and silver

Metallic materials usually exist in polycrystalline form. Grain boundaries in these polycrystalline structures form planar defects, which are paths of strongly enhanced atomic mobility. Impurity atoms tend to segregate in the grain boundaries and may result in brittleness or intergranular crack under load. We have investigated grain boundary diffusion and solute segregation of some selected solutes (Ag, Ge, Bi) in arbitrary high angle grain boundaries and in crystallographically well defined bicrystal interfaces in copper in the conditions of thermodynamic equilibrium. The most suitable method for these studies is the radiotracer technique, which is sufficiently sensitive to detect very low absolute solute concentrations in the grain boundaries. Linear and non-linear segregation behaviour was investigated allowing to determine quantitatively the segregation coefficients, segregation enthalpies and so far in the case of Ag in Cu the whole segregation isotherm.

Drittmittelgeber:

Deutsche Forschungsgemeinschaft

Beteiligte Wissenschaftler:

Dr. B. Baretzky (MPI für Metallforschung Stuttgart), Dr. S. V. Divinski, Prof. Dr. Chr. Herzig (Leiter), Dipl.-Phys. M. Lohmann

Veröffentlichungen:

Divinski, S. V., M. Lohmann, Chr. Herzig: On the physical meaning of the segregation coefficient, determined by tracer diffusion measurements in Harrisons B- and C-type regimes - results on Ag and Cu polycrystals Defect and Diffusion Forum, 194 - 199, 1127 (2001)

Divinski, S. V., M. Lohmann, T. Surholt, Chr. Herzig: Grain boundary motion during Ag and Cu grain boundary diffusion in Cu polycrytals Interface Science, 9, 357 (2001)

Divinski, S. V., M. Lohmann, Chr. Herzig: Grain boundary diffusion and linear and non-linear segregation of Ag in Cu, Interface Science, 11, 12 (2002)