Multiscale modeling of crystal plasticity in Reactor Pressure Vessel steels: Prediction of irradiation hardening

The plastic behavior of irradiated Reactor Pressure Vessel (RPV) steels is described by constitutive equations capturing the temperature and strain rate sensitivities. The flow stress is decomposed into its fundamental components associated with the microstructure features peculiar to RPV steels, such as carbides, dislocation network and deformation confinement inside grains. Dislocations are assumed to move on the {110} and {112} crystallographic planes and a simplified interaction matrix is proposed. The predicted yield stress is obtained without adjustable parameters and found in close agreement with a large number of experimental results over a large temperature range. Finally, the contribution of radiation defects is accounted for using atomistic and dislocation dynamics results. The effect of solute cluster is analyzed in details in terms of the cluster size and density and strength. Results are discussed and compared with an experimental database on neutron-irradiated RPV steels.