It was noted that, in the γ-phase, the critical resolved shear stress for <110] slip was greater than the critical resolved shear stress for <011] slip by a factor of about 2. A simple explanation for this numerical relationship was given which made use of the properties of the dissociation structures of ½<110] ordinary dislocations and <011] superlattice dislocations. This explanation showed that the observed difference in the critical resolved shear stresses was only a superficial difference. The 2 types of dislocation were fundamentally quite similar in that they possessed an identical component, in the core structure, which resulted in the same lattice frictional force. This also explained the very similar response of the 2 slip systems to temperature changes. It was concluded that <011] was the easy-slip mode simply because the <011] super-dislocation possessed a highly mobile component which magnified the total force that was exerted, but did not contribute to the lattice frictional force.

An Example Supporting the Importance of Dislocation Core Structure - an Explanation of the Relative Yield Stresses of <110] and <011] Slips in γ-TiAl. Y.Q.Sun: Philosophical Magazine Letters, 1999, 79[12], 897-900