New cyclic crystal viscoplasticity model based on combined nonlinear kinematic hardening for single crystals

Based on the existing experimental data of cyclic deformation for copper single crystal, a face centred cubic crystal, a new cyclic constitutive model was developed in the framework of single crystal viscoplasticity. In the developed model, a combined nonlinear kinematic hardening model was introduced and the remarkable cyclic hardening of copper single crystal was described by the progressive evolution of back stress and isotropic deformation resistance in each slip system. The self- and latent-hardening of dislocation slip in the different slip systems were considered by employing an interaction hardening matrix H. The proposed model is first verified by comparing the simulated results with some referable experimental data. And then, the capability of the model to describe the uniaxial ratcheting of copper single crystal is discussed, even if the corresponding experimental data cannot be referred now yet.