Interactions between interstitial impurities and dislocations were observed by means of transmission electron microscopy. Diffraction contrast images revealed evidence for the decoration, by small precipitates, of ordinary dislocations with a Burgers vector of ½<110]. These were present both in sub-grain boundaries and isolated in grain interiors. Electron energy-loss spectroscopy indicated that these precipitates were enriched in O with respect to the TiAl matrix, and may have formed oxides. On the basis of the contrast which was exhibited by these decorated defects in weak-beam images, a maximum diameter of about 10nm was determined for the precipitates. A model was proposed for the interaction between interstitial solute atoms and dislocations.

Interaction of Dislocations and Interstitial Solute in γ-TiAl J.M.K.Wiezorek, H.L.Fraser: Philosophical Magazine A, 1998, 77[3], 661-74