Resolving Overlapping EBSD Patterns by Experiment -- Simulation Residuals Analysis

TL;DR

This paper introduces an iterative simulation-based method for resolving overlapping Kikuchi diffraction patterns in EBSD, significantly enhancing phase detection accuracy without prior orientation knowledge.

Contribution

The authors develop a novel iterative approach using simulated patterns and residual analysis to identify multiple phases in overlapping EBSD signals, overcoming limitations of traditional single-phase assignment.

Findings

Improved detection of minor phases in complex materials.

No need for known orientation relationships between phases.

Enhanced phase identification accuracy in overlapping patterns.

Abstract

In the technique of Electron Backscatter Diffraction (EBSD), the accurate detection and identification of different phases existing in a sample is often limited by overlapping Kikuchi diffraction patterns originating from the extended probing volume of the individual EBSD map points measured in the scanning electron microscope (SEM). We present an iterative approach that uses simulated Kikuchi patterns to resolve several overlapping diffraction signals. For each measured EBSD pattern, our method first identifies the best-fit simulated Kikuchi pattern using dynamic template matching. This simulated, ideal reference pattern is then further processed to optimally match the experimental image, uncovering any underlying weaker signals after subtraction. Repeatedly utilizing dynamic template matching and pattern subtraction on residual signals of subsequent steps enables the identification of minor phases that might otherwise be missed from the probing volume of the EBSD map point. This method significantly improves phase detection in complex materials, addressing a key limitation of conventional EBSD analysis that conventionally assigns a single phase to each map point. The present method does not require a known orientation relationship between the phases of the overlapping patterns or close neighbor experimental patterns like previously published approaches.