Abstract: The dislocation ledges at the α2/7 intedece in a hot-dejormed Ti-45Al-10N alloywere analyzed by high-resolution tmnsmission electron microscopy. A new type ofdislocation ledge containing 1/3[111] Frank partial was found. The height of the ledgestDas always three [111]γplanes. The Burpers vectore of these diBlocation ledges weredetermined to be 1/2[110] and 1/2<101] corresponding to the 90 dey. and 30 deg.Shockley partials at noral ledges, i.e. 90 dep. ShockIey Partial dislocation +1/3[111]Frank partial dislocation; and 30 deg. Shockley partial dislocation + 1/3[111] Frankparfial dislocations. The jormation mechanism of this new tare of dislocation ledgewas discussed.

Key words: titanium aluminide, thermomechanical treatment, phase interface, tmnsmission electron microscopy