Ordinary dislocations in γ-TiAl: Cusp unzipping, jog dragging and stress anomaly

Abstract

Two models recently proposed for strength anomalies in TiAl were based on different behaviours of jogs: in the first, jogs are supposed to move conservatively along the screw direction, whereas in the other, screw dislocation motion is supposed to be controlled by jog or dipole dragging. In the present paper, we compute the flow stresses expected in both cases. The former model is shown to operate up to the stress peak temperature, and to be replaced by the latter as temperature is raised above the peak.