Accurate grain boundary plane distributions for textured microstructures from stereological analysis of orthogonal two-dimensional electron backscatter diffraction orientation maps

TL;DR

This paper introduces a stereological method using three orthogonal EBSD maps to accurately estimate grain boundary plane distributions in textured microstructures, overcoming biases from single-plane analysis.

Contribution

The method combines data from three orthogonal sections to improve qualitative accuracy of GBPD in textured microstructures, addressing limitations of existing stereological approaches.

Findings

Successfully applied to synthetic microstructures with hexagonal and tetragonal symmetries.

Overestimates GBPD anisotropy but retains qualitative usefulness.

Combining three orthogonal sections yields reliable GBPD results.

Abstract

We present a method for obtaining qualitatively accurate grain boundary plane distributions (GBPD) for textured microstructures using a stereological calculation applied to two-dimensional electron backscatter diffraction (EBSD) orientation maps. Stereology, applied to 2D EBSD orientation maps, is currently the fastest method of obtaining GBPDs. Existing stereological methods are not directly applicable to textured microstructures because of the biased viewing perspectives for different grain boundary types supplied from a single planar orientation map. The method presented in this work successfully removes part of this bias by combining data from three orthogonal EBSD orientation maps for stereology. This is shown here to produce qualitatively correct GBPDs for heavily textured synthetic microstructures with hexagonal and tetragonal crystal symmetries. Synthetic microstructures were generated to compare the stereological GBPD to a known ground truth, as the true GBPD could be obtained from a triangular mesh of the full grain boundary network in 3D. The triangle mesh data contained all five macroscopic parameters to fully describe the grain boundary structure. It was observed that our stereological method overestimated the GBPD anisotropy. However, qualitative analysis of the GBPD remains useful. Furthermore, it was found that combining data from three orthogonal sections gives reliable results when sectioning the texture's primary axes.