Deformation of microstructurally refined cast Ti46Al8Nb and Ti46Al8Ta

► Ductility difference established between Ti46Al8Nb and Ti46Al8Ta despite similar microstrucures. ► Activity of c-component dislocations in alpha2 occurs in both alloys when suitably oriented with respect to stress axis. ► Very large elastic stresses can be built up at gamma/alpha2 interfaces. ► These large elastic stresses can generate dislocations in gamma at the opposite interface without any activity within the alpha2.