A combined experimental and strain gradient crystal plasticity framework is presented for studying the development of orientation and misorientation gradients at the grain boundaries during plastic deformation. The regions in the vicinity of prior-deformation grain boundaries experience localized plastic deformation and are referred to as Near Boundary Gradient Zones (NBGZs). Deformed microstructures of an aluminum–magnesium (Al–6wt.% Mg) alloy are studied using Electron Back Scattered Diffraction (EBSD) during progressive tensile deformation. Orientation and misorientation gradients at the prior-deformation grain boundaries are quantified on grain pairs with different combinations of crystallographic orientations. Realistic virtual microstructures are then simulated using a strain gradient crystal plasticity finite element framework to study the evolution of local misorientations, stresses and strains and their correlation with the underlying substructure. The simulated microstructures indicate that the average profiles of the Geometrically Necessary Dislocation (GND) density correlates with the local misorientation, while the average profiles of the Statistically Stored Dislocation (SSD) density correlates with the effective plastic strain in these NBGZs. The combined experimental and modeling analysis reveals that the width (mean with deviation) of the distribution of the length of NBGZs, normalized by the grain size, scales with the initial grain-average Schmid factor. Further, our results also suggest a possibly strong correlation between the length of the NBGZ and the grain size.

提出了一种组合的实验和应变梯度晶体塑性框架，用于研究塑性变形过程中晶界处取向和取向差梯度的发展。先前变形晶界附近的区域经历局部塑性变形，被称为近边界梯度区（NBGZ）。在渐进拉伸变形过程中，使用电子背散射衍射 (EBSD) 研究了铝镁 (Al-6wt.% Mg) 合金的变形微观结构。在具有不同结晶取向组合的晶粒对上量化了先验变形晶界处的取向和取向错误梯度。然后使用应变梯度晶体塑性有限元框架模拟真实的虚拟微观结构，以研究局部错误取向、应力和应变的演变及其与底层子结构的相关性。模拟的微观结构表明几何必要位错 (GND) 密度的平均分布与局部错误取向相关，而统计存储位错 (SSD) 密度的平均分布与这些 NBGZ 中的有效塑性应变相关。结合实验和建模分析表明，NBGZ 长度分布的宽度（有偏差的平均值）由晶粒尺寸归一化，与初始晶粒平均施密德因子成比例。更远，