Crystal stress distribution evolution of elastoplastically deforming polycrystals over crystal orientation space

As techniques for measuring and modeling crystal stresses have become increasingly available, a more thorough investigation of crystalline solids' behavior is possible. As experimental techniques that are suitable for investigating synchrotron X-ray diffraction are developed, stress tensors of plastically deforming polycrystalline solids can be obtained. In this study, the mechanism behind the stress tensor evolution of plastically deforming polycrystalline solids is presented. From a simulation model that has been calibrated with the X-ray synchrotron results of a copper specimen under uniaxial tension, the elastoplastic behavior of deforming polycrystals is analyzed. This analysis determined that the crystal stress distributions depend heavily on the crystal orientation. To provide insights into the crystal stress evolution during plastic flow, the angular distance (proximity) between the crystal stress direction and the single crystal yield surface vertices were used to investigated the preferred crystal stress direction, its evolution pattern, and the applied loading direction. This confirms that, as plasticity develops, crystal stress tends to move toward the closest vertex of the single crystal yield surface from the applied loading direction.