The level of residual stress in a metal polycrystal is determined by the deformation history, the properties of single crystals, and the nature of grain interactions. In this presentation, we discuss the modeling of plastic deformation of aluminum and steel alloys with the intent of resolving residual stresses at the crystal level and exposing trends that arise from grain interactions. Using the finite element method, we model polycrystals grain by grain. Simulated responses are compared to measured values from a coordinated set of experiments. In the experiments, tensile specimens were loaded, unloaded, and reloaded to progressively larger amounts of plastic strain while positioned within a neutron diffractometer. Measurements were taken at various points in the loading history, thereby providing the average elastic lattice strains in designated sets of crystals and allowing for direct comparison to simulation. The simulations also provide information on the variations in strains from the average values that stem from crystal orientation and from interactions among neighboring crystals. The strain variations with rotation about the scattering vector can be substantial, and each crystal direction shows its own signature.
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