The flow stress anomaly, between 200 and 800K, of Ni3Al single crystals was examined by simulating the dislocation dynamics at a mesoscopic scale. The basic simulation rules were that dislocation glide occurred on {111} octahedral planes, that screw lines were locked and unlocked by the formation of Kear-Wilsdorf locks and that jogs were mobile on the {100} cube plane. The results suggested that two different temperature regimes existed within the domain of the anomaly. At low temperatures, the plastic flow was governed by kink bow-out; itself a function of the kink length. At high temperatures, the plastic flow was governed by the unlocking of the weakest Kear-Wilsdorf locks in the microstructure.

Modeling of the Dislocation Dynamics in Ni3Al and the Flow Stress Anomaly. Devincre, B., Veyssiere, P., Kubin, L., Saada, G.: Materials Research Society Symposium – Proceedings, 1997, 460, 535-40