Discrepancy Between Crystal Plasticity Simulations and Far-Field High-Energy X-ray Diffraction Microscopy Measurements

three-dimensional dataset of Inconel-625 generated as part of the Air Force Research Laboratory’s Additive Manufacturing Challenge Series is considered to interrogate modeling errors in a crystal-plasticity finite-element (CPFE) framework. Grain-average elastic strains from this framework are compared to measurements made with far-field high-energy X-ray diffraction microscopy (ff-HEDM) on a specimen loaded in tension at room temperature. The ff-HEDM measurements, taken when the specimen was held under load control, were made on the same microstructure considered in the CPFE framework. This one-to-one comparison enables a thorough investigation into modeling discrepancies, specifically those induced by improper boundary condition selection and inability to model stress relaxation events which are a likely characteristic of intermittent plasticity. It is shown that erroneously constraining the Poisson effect locally with kinematic boundary conditions induces over-estimates of off-loading-axis normal strains as far as 100 m away from the over-constrained surface, which is roughly 14