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G. Stechauner, E. Kozeschnik:
"Self-Diffusion in Grain Boundaries and Dislocation Pipes in Al, Fe, and Ni and Application to AlN Precipitation in Steel";
Journal of Materials Engineering and Performance, 23 (2014), 5; 1576 - 1579.

Diffusion along microstructural defects, such as grain boundaries or dislocation pipes, is significantly faster than diffusion through an undisturbed crystal. The ratio of diffusion enhancement is 3-4 orders of magnitude close to the melting point and reaches up to several ten orders of magnitude close to room temperature. An assessment of literature shows a large scatter in the available data and emphasizes the need for representative mean values. Applying a least mean square fit to selected experimental information delivers temperature-dependent functions for the ratio of grain boundary and dislocation pipe to bulk diffusion, respectively. We demonstrate that application of the attained results in a computational framework for the kinetics of precipitation makes the predictive simulation possible for the evolution of particles located at dislocations and grain boundaries.

carbon/alloy steels, diffusion, dislocation, grain boundary, thermokinetic simulation

http://dx.doi.org/10.1007/s11665-014-0921-z