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

Abstract

In Al-rich γ-TiAl deformed at room temperature, <011] dislocations dissociate in general into a ⅙<112] partial and a ⅙<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, ½<112] dislocations are sessile by-products of the decomposition of <011] dislocations and that, despite a significant relative abundance, they hardly contribute to strain.