An extended crystal plasticity model to simulate the deformation behaviors of hybrid stress–strain controlled creep-fatigue interaction loading

A numerical process based on crystal plasticity finite element method was implemented to describe the cyclic stress–strain response and especially the creep deformation of 9 %Cr steel under hybrid stress–strain controlled creep-fatigue interaction loading at 650 °C. An extended model based on Armstrong and Frederick (A-F) hardening law was used to capture the creep strain. Compared with experimental results, the creep strain performed by A-F model was small while extended model predicted well. The cyclic softening and decline tendency of relaxation have been simulated. Simulations of other loading modes with extended model also show a good agreement with experimental results.