A Study of Grain Boundary Structure and Transformations Utilizing the Faceting Phenomenon in a Cooper-Bismuth Alloy

本研究以掺杂铋铜中溶质偏析形成的原子平面晶界面为模型体系，研究了双组分合金中晶界成分与组织的关系及组织演化。主要实验工具是常规和高分辨率透射电子显微镜（HREM）。该方法是识别两个相邻晶粒中特定取向错误的facet平面的晶体学取向，然后通过HREM确定facet中铋原子的位置。这些结果与原子计算相比较。作为时间和退火温度的函数，研究了facet类型的演变。这项研究提供了原子尺度结构和晶界偏析化学的重要信息。晶界对多晶材料的物理性能起着重要的决定作用。

This research employs the atomically flat grain-boundary facets which form as the result of solute segregation in bismuth-doped copper as a model system with which to study the relationship between grain boundary composition and structure and the evolution of structure in a two component alloy. The principal experimental tools are conventional and high-resolution transmission electron microscopy (HREM). The approach is to identify crystallographic orientations of the facet planes in each of two abutting grains for a grain pair of specific misorientation, and then determine the location of the bismuth atoms in the facets by HREM. These results are compared to atomistic calculations. Evolution of facet types is examined as a function of time and annealing temperature. %%% This research provides important information about the atomic-scale structure and chemistry of segregation at grain boundaries. Grain boundaries play an important role in determining the physical properties of polycrystalline materials.