Plastic Deformation in ODS Ferritic Alloys: A 3D Dislocation Dynamics Investigation

Discrete dislocation dynamics simulations were carried out to examine mechanical behavior of ferritic steel strengthened with Oxide Dispersion Strengthening (ODS) particles. Interplay of irradiation induced defect clusters and the ODS precipitates and its effect on the strain localization and hardening of the material is investigated. These simulations show that, in the absence of irradiation, the ODS particles act as an impediment to the dislocation motion and hence lead to greater strain localization, when subjected to uni-axial tensile deformation. After irradiation, however, it is seen that the presence of interstitial loops in the material reverses this trend. That is, presence of particles act against the detrimental effect of irradiation induced defect microstructure and helps in reducing strain localization. The hardening behavior also exhibits the same trend. Our study indicates that the irradiatio n induced hardening is suppressed by the presence of strengthening particles.