Dose-dependent strain localization and embrittlement in ferritic materials: A predictive approach based on sub-grain plasticity modelling

Abstract

This paper presents a theoretical approach addressing plastic-strain spreading in post-irradiated BCC materials accounting for crucial sub-grain scale, dislocation-mediated plasticity mechanisms. The proposed model explicitly provides the number of shear-bands developed in irradiated ( N i r r ) versus non-irradiated ( N 00 d p a ) grain cases, for fixed amounts of plastic deformation. Calculations carried out under various irradiation defect size and number density cases, which helps it appraising important material properties, in particular the dose-dependent, grain-scale uniform elongation threshold. The model ability to handle macro-scale effects is then evaluated using a simple stochastic calculation procedure, taking advantage of actual grain size and orientation maps. The dose-dependent embrittlement amplitude appears to critically depend on the shear band thickness and spacing variations, existing near the fracture surface of failing specimens. That perception allows comparing our predictions with adapted test results, for validation.