The flow stress anomaly was studied by means of a mesoscopic 2-dimensional simulation of the dislocation dynamics. The basic properties which were modelled were slip in the octahedral plane, the conditions under which screw dislocation segments were locked by the formation of Kear-Wilsdorf locks and then unlocked, and the mobility of jogs on the cube plane. The range of temperatures which was investigated ranged from 200 to 600K. The simulated results indicated that strain occurred mainly via the sliding of kinks. It was noted that 2 conditions had to hold simultaneously in order to reproduce the flow stress anomaly. Firstly, kink mobility had to be hindered by the dragging of jogs. Secondly, regardless of the probability of locking, such locks were not to be easily destroyed. The simulated results also suggested that 2 different flow stress regimes existed within the temperature domain of the stress anomaly. At the onset of the anomaly, the flow stress was determined by kink motion, which was itself a function of kink height. However, in the high-temperature regime, the flow stress was governed by unlocking of the weakest incomplete Kear-Wilsdorf lock in the microstructure.

Simulation of Dislocation Dynamics and the Flow Stress Anomaly in L12 Alloys. B.Devincre, P.Veyssière, L.P.Kubin, G.Saada: Philosophical Magazine A, 1997, 75[5], 1263-86