As a result of experiments which included plastic deformation and subsequent heating without stress, self-blocking of dislocations in TiAl was revealed. The transformations of glissile dislocations into dislocation barriers was observed both for super-dislocations with Burgers vectors <101] and 1/2<112] and for single dislocations. The preliminary deformation was performed at room temperature; the heating without stress, at temperatures both below and above the peak temperature T max in the temperature dependence of the yield stress σy(T). With a proper choice of the temperature of heating and its duration, it proved to be possible to fix the initial stages of the straightening of single dislocations along a preferred direction parallel to their Burgers vector and the subsequent formation of long blocked dislocations. As a result of TEM analysis, it was shown that the barriers were formed during heating without stress but they were not destroyed. It was revealed that the barriers with a total Burgers vector <101] in TiAl, in contrast to Ni3Al, remained indestructible even when the experiments included a repeated deformation.

Some Features of the Formation and Destruction of Dislocation Barriers in Intermetallic Compounds - IV. Thermoactivated Straightening of Dislocations Along a Preferred Direction in TiAl. B.A.Greenberg, O.V.Antonova, A.Y.Volkov, M.A.Ivanov, N.A.Kruglikov, Y.P.Kadnikova: The Physics of Metals and Metallography, 2008, 105[5], 491-9