Dissociation of super-dislocations and the SISF energy in c-TiAl based alloy with Nb-doping, as studied by HRTEM

The dissociation of super-dislocations in c-TiAl in Nb-doped Ti-48 at.% Al-5 at.% Nb has been studied by high resolution transmission electron microscopy (HRTEM). The SISF energy in c-TiAl in Ti-48 at.% Al-5 at.% Nb was calculated to be 35 mJ/m2 according to the dissociation width. It is concluded that Nb addition may affect the electronic structure of TiAl and furthermore decrease SF energies in TiAl alloys, which is partly responsible for the strengthening effect of Nb-doping.