Dependence of crystal stress evolution on the vertices of the single crystal yield surface and the effect from the intergranular misorientation during plastic deformation

Understanding the behavior of deforming materials is essential for better designing innovative materials and identifying damage of materials in service. However, most engineering materials are polycrystalline and, due to the complex behavior of polycrystalline solids, in-depth analysis could not be readily conducted. As techniques such as the high-energy X-ray synchrotron experiment become available, findings from simulation can now be supported by real observation and vise versa. Using the synergic tool of combining the experiment and simulation, it has been shown that the crystal stress directions over the polycrystal aggregates are moving toward the vertices of the single crystal yield surface (SCYS). In this research, the crystal stress evolution pattern at a single crystal during plastic flow is investigated using the simulated data from finite element analyses. By investigating the crystal stress evolution of the same crystal with rearranged neighboring crystals with the same set of orientations, the effect of the intergranular misorientation on the crystal stress evolution is investigated. For the virtual specimens investigated in this study, the intergranular misorientation for the immediately neighboring grains are quantified. Then, through finite element simulations, it is confirmed that the crystal stress is not only dependent on the crystal orientation itself but also on the misorientation with the surrounding crystals. The crystal stress/strain levels for the same crystal with different intergranular misorientation are not identical since the different misorientation distributions affect the way that the grains interact. The crystal stress directions are moving toward the SCYS vertex during plastic flow but the closest vertex distributions show differences when the intergranular misorientation is changed.