EBSD analysis of orientation gradients developed near grain boundaries

Abstract

The local misorientation and orientation gradient development near grain boundaries (GBs) are analyzed in a deep drawing quality steel sheet (AKDQ) subjected to interrupted tensile tests in a notched sample. The microstructure is studied using electron backscatter diffraction (EBSD) with subgrain-level spatial resolution. The evolution of misorientation accumulation for particular GBs was traced in grains located in different zones inside the notch, identifying the effective area of influence of GBs inside the neighboring grains. A local study was performed, and the evolution in misorientation development near GB was investigated. The results show a low correlation between GB width and sharpness of the orientation gradient with the mesoscopic strain, but instead orientation gradients between GB zones and the interior of the grains were observed with increasing strain. The increase in severity observed in some GBs can be related to dislocation pile up development, which reduces the permeability of a boundary to dislocation transmission.