Dislocation structures of TiAl single crystals compressed along the [(1)over-bar10] and [(1)over-bar32] directions at room temperature

In this study, single crystals of TiAl with low oxygen contents were prepared under ultra-clean inert gas using a tri-arc crystal puller. Samples were compressed up to 1-2% at room temperature along the [(1) over bar 10] and [(1) over bar 32] directions, which have maximum Schmid factors for <101] superdislocations and 1/2<110] ordinary dislocations respectively. The former was dominated by <101] superdislocations with double dissociations and interval cusps of 1/6<112] faulted dipoles. The latter gave a high density of faulted dipoles bounded by 1/6<112] and 1/3<121] partial dislocations. The decomposition of <101] superdislocations was found to be controlled by the shear stress components on 1/2<110]{111} slip systems.