A practical SEM-EBSD-FIB workflow for local grain boundary plane determination in Ti-6Al-4V

Grain boundary plane (GBP) orientation is a key descriptor of grain boundary character and strongly influences interfacial processes such as solute segregation, precipitation and phase transformation. Conventional two-dimensional imaging and orientation mapping based on scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD), however, provide only a grain boundary trace on a polished surface and therefore cannot uniquely determine the local three-dimensional GBP. Here we present a practical workflow that combines SEM/EBSD with site-specific focused ion beam (FIB) sectioning to reconstruct the local GBP from two experimentally accessible traces of the same grain boundary segment: the surface trace measured on the SEM/EBSD section and a second trace revealed on an FIB cross-section. After registering the two trace vectors into a common EBSD reference frame, the GBP normal is obtained from their cross product. Using a grain boundary α segment in Ti-6Al-4V as a worked example, we demonstrate how the reconstructed local GBP can be represented in the EBSD and crystal reference frames to quantify its geometric relationships with candidate habit planes and invariant-line-related directions.