The deformation mechanisms and dynamic recrystallization (DRX) behavior of specifically grown bicrystals with a symmetric 90° and 90° tilt grain boundary, respectively, were investigated under deformation in plane strain compression at 200 °C and 400 °C. The microstructures were analyzed by panoramic optical microscopy and large-area electron backscatter diffraction (EBSD) orientation mapping. The analysis employed a meticulous approach utilizing hundreds of individual, small EBSD maps with a small step size that were stitched together to provide comprehensive access to orientation and misorientation data on a macroscopic scale. Basal slip primarily governed the early stages of deformation at the two temperatures, and the resulting shear induced lattice rotation around the transverse direction (TD) of the sample. The existence of the grain boundary gave rise to dislocation pile-up in its vicinity, leading to much larger TD-lattice rotations within the boundary region compared to the bulk. With increasing temperature, the deformation was generally more uniform towards the bulk due to enhanced dislocation mobility and more uniform stress distribution. Dynamic recrystallization at 200 °C was initiated in -compression twins at strains of 40% and higher. At 400 °C, DRX consumed the entire grain boundary region and gradually replaced the deformed microstructure with progressing deformation. The recrystallized grains displayed characteristic orientations, such that their c-axes were perpendicular to the TD and additionally scattered between 0° and 60° from the loading axis. These recrystallized grains displayed mutual rotations of up to 30° around the c-axes of the initial grains, forming a discernible basal fiber texture component, prominently visible in the pole figure. It is noteworthy that the deformation and DRX behaviors of the two analyzed bicrystals exhibited marginal variations in response to strain and deformation temperature.

中文翻译：

---

90°[略式]和90°[略式]倾斜晶界镁双晶高温变形及再结晶行为

研究了分别具有对称 90° 和 90° 倾斜晶界的特殊生长双晶在 200 °C 和 400 °C 平面应变压缩变形下的变形机制和动态再结晶 (DRX) 行为。通过全景光学显微镜和大面积电子背散射衍射（EBSD）取向图分析微观结构。该分析采用了细致的方法，利用数百个单独的、步长较小的小型 EBSD 地图，将这些地图拼接在一起，以提供对宏观尺度上的方向和方向错误数据的全面访问。基底滑移主要控制两个温度下变形的早期阶段，以及由此产生的剪切引起的晶格绕样品横向（TD）的旋转。晶界的存在导致其附近出现位错堆积，导致晶界区域内的 TD 晶格旋转比块体大得多。随着温度升高，由于位错迁移率增强和应力分布更均匀，变形通常朝向体块变得更均匀。应变为 40% 或更高时，压缩孪晶在 200 °C 下开始动态再结晶。在 400 °C 时，DRX 消耗了整个晶界区域，并随着变形的进展逐渐取代变形的微观结构。再结晶晶粒显示出特征取向，使得它们的 c 轴垂直于 TD，并且另外分散在距加载轴 0° 和 60° 之间。这些再结晶晶粒围绕初始晶粒的 c 轴显示出高达 30° 的相互旋转，形成可辨别的基底纤维织构成分，在极图中清晰可见。值得注意的是，两种分析双晶的变形和 DRX 行为对应变和变形温度的响应表现出边际变化。