A High-Resolution Three-Dimensional Electron Backscatter Diffraction Study of the Nucleation of Recrystallization in Cold-Rolled Extra-Low-Carbon Steel

The crystallographic nature of the early stages of recrystallization within a volume of deformation microstructure in cold-rolled extra-low-carbon (ELC) steel was investigated by three-dimensional (3-D) electron backscatter diffraction (EBSD). The investigation revealed several pertinent restoration events not easily observed on two-dimensional (2-D) polished sections, including the following: (1) demonstration that each nucleus is formed with an orientation contained within its local deformation substructure, (2) observation of a single nucleus containing both a dislocation-containing core and protruding dislocation-free high-angle grain-boundary (HAGB) segments, and (3) preferential growth of certain HAGB segments into the surrounding highly misoriented regions of the deformation substructure. The technique, therefore, provided the unambiguous observation of the nucleation of grains with orientations within the spread of the local deformation substructure followed by the preferred growth of certain boundary segments; this is consistent with the concept of oriented nucleation followed by growth controlled by orientation-pinning effects.