Techniques for generating 3-D EBSD microstructures by FIB tomography

This work describes some techniques developed for focused ion beam (FIB) serial sectioning and electron backscatter diffraction (EBSD) mapping of partially and fully recrystallized metals. A DualBeam™ platform was used to sequentially mill submicron slices of a material by FIB with the crystallographic features of each newly created surface characterized by EBSD. Two promising milling procedures are described which involve: (i) the generation of a small (∼ 10–50 μm) diameter whisker for subsequent serial sectioning perpendicular to its long axis, and (ii) more extensive FIB milling of a larger sample to generate a protruding rectangular-shaped volume at the free surface. The latter was found to be the more powerful method of serial sectioning as the initial preparation is slightly less tedious. Using both techniques, serial sectioning was carried out on both recrystallized iron and partly recrystallized nickel samples. The serial sectioning technique revealed a number of features of the recrystallizing grains in nickel that are not clearly evident in 2-D EBSD micrographs.