Dissociations of super-dislocations in γ-TiAl in Nb-doped Ti-48Al-1at%Nb and Ti-48Al-10at%Nb were studied by high resolution transmission electron microscopy and weak-beam transmission electron microscopy. The self-interstitial stacking-fault energy was calculated to be 63mJ/m2 in Ti-48Al-1at%Nb and 34mJ/m2 in Ti-48Al-10at%Nb, respectively; according to the dissociation width. Consequently, it was concluded that Nb-additions could decrease the SF energy significantly, which obviously contributed to the strengthening effect induced by Nb-doping.

Dissociation of Super-Dislocations and the Stacking Fault Energy in TiAl Based Alloys with Nb-Doping. Y.Yuan, H.W.Liu, X.N.Zhao, X.K.Meng, Z.G.Liu, T.Boll, T.Al-Kassab: Physics Letters A, 2006, 358[3], 231-5