Atomic-scale observations and 3-dimensional analyses of a Cottrell atmosphere were performed by means of 3-dimensional atom-probe field-ion microscopy. The ability of this new method to provide atomic-resolution images was confirmed by obtaining the basic stacking structure of the (001) planes. The presence of an <001> edge dislocation was also detected in the analysed zone. Moreover, B-enrichment was measured in the vicinity of the defect. The B-rich region appeared as a pipe which was 5nm in diameter and was parallel to the dislocation line. The B concentration in the core attained 3at%, and this local B-enrichment was associated with an Al depletion of more than 10at%. It was recalled that B in FeAl had a well-known tendency to segregate to internal interfaces, and the present work provided experimental evidence of solute segregation to dislocation lines.

Investigation of Boron-Enriched Cottrell Atmospheres in FeAl on an Atomic Scale by Three-Dimensional Atom-Probe Field-Ion Microscopy. E.Cadel, S.Launois, A.Fraczkiewicz, D.Blavette: Philosophical Magazine Letters, 2000, 80[11], 725-36