A 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 \(\upmu \)m away from the over-constrained surface, which is roughly 14% of the overall height of the polycrystal in the loading direction. A second set of boundary conditions that relaxes the constraints on the previously over-constrained surface showed clear quantitative improvement in model predictions. Specifically, the errors in the normal components of strains in the off-loading-axes decreased. Further, it was observed that irrespective of which of the two boundary conditions was applied, the CPFE framework deviates considerably from measurements in the plastic regime compared to the elastic regime. This is mainly due to the increased frequency of strain drop (or stress relaxation) events occurring in the plastic regime, most likely caused by shearing of \(\gamma ^{\prime}\) precipitates and other intermittent dislocation activity. The CPFE framework is unable to accommodate the stress relaxation in grains. Nevertheless, the framework is interrogated for its ability to predict such events by comparing predicted slip fields with measured grain-level relaxation events. It is demonstrated that the set of grains experiencing a strain drop (from ff-HEDM measurements) collectively had higher values of plastic strain (calculated from CPFE simulations) compared to the set of grains that did not experience a strain drop.

作为空军研究实验室“增材制造挑战系列”的一部分生成的Inconel-625三维数据集被认为是在晶体塑性有限元（CPFE）框架中询问建模错误。将来自此框架的晶粒平均弹性应变与通过远场高能X射线衍射显微镜（ff-HEDM）在室温下加载了试样的测量结果进行了比较。当样品在负载控制下进行时，ff-HEDM测量是在CPFE框架中考虑的相同微观结构上进行的。通过一对一的比较，您可以对建模差异进行彻底的调查，特别是那些由于不适当的边界条件选择和无法建模应力松弛事件而引起的应力，这些应力松弛事件可能是间歇性可塑性的特征。结果表明，在运动学边界条件下错误地限制了泊松效应，导致卸载轴法向应变高估了100 距过度约束的表面\（\ upmu \） m，大约是多晶体在加载方向上的总高度的14％。第二组边界条件可以放宽对先前过度约束的表面的约束，从而在模型预测中显示出明显的定量改进。具体地，卸载轴中的应变的正常分量的误差减小了。此外，观察到，无论应用两个边界条件中的哪一个，与弹性状态相比，CPFE框架都与塑性状态下的测量有很大差异。这主要是由于塑性状态下发生应变下降（或应力松弛）事件的频率增加，最有可能是由于剪切了\（\ gamma ^ {\ prime} \）沉淀和其他间歇性位错活动。CPFE框架无法适应晶粒的应力松弛。然而，通过比较预测的滑移场和测得的晶粒水平弛豫事件，对框架预测此类事件的能力提出了质疑。结果表明，与未经历应变下降的一组晶粒相比，经历了应变下降的一组晶粒（根据ff-HEDM测量）总体上具有较高的塑性应变值（根据CPFE模拟计算）。