Loi de comportement en plasticité cristalline pour acier à basse température

Abstract

The prediction of the irradiation-induced evolution of the ductile-fragile transition curve of pressure vessel steels is a major research topic in the nuclear industry. Multiscale approaches starting from ab initio scale up to macroscopic continuum mechanics are currently investigated through the European project PERFORM60. At the intermediate level of cristal plasticity, several effects need to be described accurately before considering the introduction of irradiation hardening mechanisms, such as the thermal activity of dislocations slip, the different mobilities between screw and edge dislocations at low temperature. These effects should be introduced in a cristal plasticity law used in finite-element simulations of polycrystalline aggregates. Accordingly, a new cristal plasticity law is proposed in this paper based on a critical analysis of previous numerical results obtained with a discrete dislocations dynamics code. © AFM, EDP Sciences 2011.