A new crystal plasticity modeling of uniaxial ratcheting behavior for face-centered cubic N6061 aluminum alloy

The uniaxial ratcheting behavior of face-centered cubic 6061 aluminum alloy is investigated theoretically based on the crystal plasticity theory. In this model, a simplified flow rule is adopted for convenient engineering application, and the classical Kocks-Mecking-Estrin isotropic hardening rule related to dislocation density is adopted to describe the cyclic hardening characteristic of the material. The classical Armstrong-Frederic kinematic hardening rule is modified associated with cumulative slip to predict the ratcheting behavior more accurately. The single crystal version of this model is expanded to metal polycrystalline using a simplified explicit scale transition rule. The capability of the proposed model to capture the uniaxial ratcheting response of metal polycrystalline is verified by comparing the predictions with the corresponding experimental results of 6061 aluminum alloy. The evolution of uniaxial ratcheting of 6061 aluminum alloy can be reasonably predicted by the proposed model, and the capability to simulate uniaxial ratcheting behavior in inter-granular scale is qualitatively discussed as well.