High-resolution electron microscopy observation of a¹/₂(112) superdislocation in TiAl

Using high-resolution electron microscopy (HREM) the core structure of a 1/2(112) superdislocation in TiAl is examined and observed to have dissociated into an extrinsic stacking fault and an intrinsic stacking fault, bounded by three 1/6(112) partial dislocations. The core structure is non-coplanar, with the extrinsic stacking fault lying on two adjacent [111] planes bounded by a dissociated b = 1/6(112) partial dislocation whose deiocalization can pin the dislocation core and may lead to the formation of ±1/6(112)dipoles.