The origin of the anomalous temperature dependence of the giant work-hardening rate and of the modest strain-rate sensitivity observed in many L12 alloys was investigated by means of a so-called end-on simulation of dislocation dynamics in Ni3Al. The present model reproduces most of the atypical mechanical properties observed experimentally. The study of the evolution of the distribution of the Kear-Wilsdorf locks during plastic deformation indicated that the order of magnitude of the work-hardening rate stemmed from a preferred exhaustion of the weakest locks. In addition, the low strain-rate sensitivity measured was found to rely on the absence of a correlation between the dislocation properties which provide the plastic strain and those which determine the flow stress level.

Simulation of the Plastic Flow in Ni3Al: Work Hardening and Strain-Rate Sensitivity. Devincre, B., Veyssière, P., Saada, G.: Philosophical Magazine A, 1999, 79[7], 1609-27