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M: Metallphysik

M 11: Diffusion und Punktdefekte III

M 11.5: Fachvortrag

Montag, 26. März 2001, 16:15–16:30, S12

Stress-driven solute migration near a slowly moving crack tip — •Peter Streitenberger and Mario Koch — Otto-von-Guericke-Universitaet Magdeburg, Institut fuer Experimentelle Physik, Abteilung Materialphysik, PSF 4120, D-39016 Magdeburg

In the present paper the solute migration towards a moving crack tip is consodered under the condition of pure drift. In the pure drift approximation it is assumed that the solute flow in the vicinity of the crack tip is dominated by the elastic interaction between the stress field of the tip and the solute atoms. Such a pure drift approach has been used to describe the migration of solute atoms to dislocations and was adopted by Rauh and Bullough to calculate the number of point defects that migrate to a stationary crack. However, for the applicability of such a calculation to a moving crack, the actual crack propagation has to be considered to proceed by periods of stops and rapid jumps rather by uniform motion. No such assumptions are necessary for the applicability of the results of the present paper, where we obtain a characteristic size of the crack tip relevant transport zone and the impurity segregation rate immediately in terms of the crack growth rate.