The Combination of Electron Backscatter Diffraction and Focus Ion Beam Microscopy to Determine Three-Dimensional Grain Orientation

Abstract

The use of electron backscatter diffraction (EBSD) to determine crystallographic grain orientations of polycrystalline metals is well known, a technique known as orientation imaging microscopy. A limitation of this technique is that the orientation maps represent a two-dimensional slice through the material microstructure. The orientation of interface planes between adjacent grain boundaries is necessarily unknown. The previous techniques for reconstructing three-dimensional (3D) microstructures relied on macroscopic serial sectioning of a sample and subsequent reimaging. The process was difficult and time consuming. Like EBSD, the use of focus ion beam microscopy to observe individual grains and the boundaries between adjacent grains using ion-channeling contrast is also well known. In this study, the abilities to locate and locally machine a grain boundary are used to determine additional 3D orientation from polycrystalline structures in both intact and partially fractured microstructures.