Influence of static strain aging on the cleavage fracture of a C–Mn steel

Abstract : Recent advances in the constitutive modeling of strain aging effects in elastoviscoplasticity are used to predict the ductile-to-brittle transition curve for a C–Mn steel depending on pre-straining and heat treatment. The parameters of the Beremin model are identified from a large experimental basis of Charpy tests. 3D finite element simulations of Charpy V-notched specimens based on a constitutive model accounting for static strain aging, are performed for the first time to predict the fracture behavior of the pre-strained and aged material. The constitutive model includes the strain localization phenomena occurring in the notch due to Lüders effects. Good agreement between experiment and modeling is demonstrated. The introduction of kinematic hardening improves the prediction of the lower part of the ductile-to-brittle transition region. The proposed approach aims at optimizing pre-strain values and heat treatments for nuclear steels.