Bennett Thomas J, Taleff Eric M
Department of Mechanical Engineering, The University of Texas at Austin, Mail Code C2200, 204 East Dean Keeton Street, Austin, TX 78712, USA.
Microsc Microanal. 2024 Nov 4;30(5):913-924. doi: 10.1093/mam/ozae092.
We present two new methods of processing data from backscattered electron signals in a scanning electron microscope to image grains and subgrains. The first combines data from multiple backscattered electron images acquired at different specimen geometries to (1) better reveal grain boundaries in recrystallized microstructures and (2) distinguish between recrystallized and unrecrystallized regions in partially recrystallized microstructures. The second utilizes spherical harmonic transform indexing of electron backscatter diffraction patterns to produce high angular resolution orientation data that enable the characterization of subgrains. Subgrains are produced during high-temperature plastic deformation and have boundary misorientation angles ranging from a few degrees down to a few hundredths of a degree. We also present an algorithm to automatically segment grains from combined backscattered electron image data or grains and subgrains from high angular resolution electron backscatter diffraction data. Together, these new techniques enable rapid measurements of individual grains and subgrains from large populations.
我们提出了两种处理扫描电子显微镜中背散射电子信号数据以成像晶粒和亚晶粒的新方法。第一种方法是将在不同试样几何形状下采集的多个背散射电子图像的数据相结合，以便（1）更好地揭示再结晶微结构中的晶界，以及（2）区分部分再结晶微结构中的再结晶区域和未再结晶区域。第二种方法利用电子背散射衍射图案的球谐变换索引来生成高角分辨率取向数据，从而能够对亚晶粒进行表征。亚晶粒是在高温塑性变形过程中产生的，其边界错取向角度范围从几度到百分之几度。我们还提出了一种算法，用于从组合的背散射电子图像数据中自动分割晶粒，或从高角分辨率电子背散射衍射数据中自动分割晶粒和亚晶粒。这些新技术共同实现了对大量单个晶粒和亚晶粒的快速测量。
