A rate-independent dislocation and defect density-based evolution model was presented that captures the pre- and post-yield material behavior of face-centered cubic metals subjected to different doses of neutron radiation. Unlike previously developed phenomenological models, this model was capable of capturing the salient features of irradiation-induced hardening, including an increase in yield stress followed by yield drop and non-zero stress offset from the non-irradiated stress-strain curve. The key contribution was a model for the critical resolved slip resistance that depended upon both dislocation and defect densities, which were governed by evolution equations based on physical observations. The result was an orientation-dependent non-homogeneous deformation model, which accounts for defect annihilation on active slip planes. Results for both single and polycrystalline simulations of OFHC copper were presented and were observed to be in reasonably good agreement with experimental data. Extension of the model to other face-centered cubic metals was straightforward, and was being developed for body-centered cubic metals.

Dislocation and Defect Density-Based Micromechanical Modeling of the Mechanical Behavior of FCC Metals under Neutron Irradiation. S.Krishna, A.Zamiri, S.De: Philosophical Magazine, 2010, 90[30], 4013-25