Crystal plasticity-based constitutive modelling of irradiated bcc structures

Abstract

A constitutive crystal plasticity model is proposed and developed for the inelastic deformation of irradiated bcc ferritic/martensitic steels. Defects found in these irradiated materials are used as substructure variables in the model. Insights from lower length- and time-scale simulations are used to frame the kinematic and substructure evolution relations of the governing deformation mechanisms. Models for evolution of mobile and immobile dislocations, as well as interstitial loops (formed due to irradiation), are developed. A rate theory-based approach is used to model the evolution of point defects generated during irradiation. The model is used to simulate the quasi-static tensile and creep response of a martensitic steel over a range of loading histories.

Keywords:

• dislocations
• radiation damage
• mechanical behaviour
• crystal plasticity
• bcc
• interstitial loops

Acknowledgements

The authors are grateful to Professor C.S. Deo and Professor T. Zhu of Georgia Tech for valuable discussions regarding this work and bridging to atomistic studies. This research has been supported by DOE NEUP award DE-AC07-05ID14517 09-269.