Properties of ⟨011]{111} slip in Al-rich γ-TiAl I.: Dissociation, locking and decomposition of ⟨011] dislocations at room temperature

In Al-rich gamma -TiAl deformed at room temperature, [011] dislocations dissociate in general into a 1/6[112] partial and a 1/6[154] partial located in the leading and trailing position respectively. Several implications of this dissociation mode on room-temperature plasticity are discussed. It is argued that, apart from load orientations where the critical resolved shear stress for [112]{111} slip is attained, 1/2[112] dislocations are sessile by-products of the decomposition of [011] dislocations and that, despite a significant relative abundance, they hardly contribute to strain.