Insights into a dual-phase steel microstructure using EBSD and image-processing-based workflow

Area of Science:

• Materials Science
• Crystallography
• Image Analysis

Background:

• Quantitative metallography relies on segmenting electron backscatter diffraction (EBSD) maps to analyze crystallographic phase morphology.
• Current image analysis tools, based on scalar images, do not fully utilize the rich crystallographic orientation data.
• Standard image processing operations need generalization to handle the unique nature of crystal orientations.

Purpose of the Study:

• To extend conventional image analysis operations (erosion, dilation, interpolation, smoothing, segmentation) for crystallographic orientation data.
• To develop a generalized framework for analyzing EBSD maps that preserves properties like frame indifference.
• To demonstrate the application of these extended methods using a dual-phase stainless steel specimen.

Main Methods:

• Development of generalized image analysis operations based on the quaternion representation of crystal orientations.
• Application of these quaternion-based methods to segment and classify crystallographic phases.
• Utilizing electron backscatter diffraction (EBSD) mapping for data acquisition.

Main Results:

• Successful generalization of image analysis operations for quaternion-represented crystal orientations.
• Accurate segmentation and classification of crystallographic phases in a dual-phase stainless steel.
• Demonstration of enhanced quantitative metallography through comprehensive EBSD map analysis.

Conclusions:

• Quaternion-based image analysis provides a robust framework for quantitative metallography using EBSD data.
• The developed methods effectively capture and process the full information content of crystal orientations.
• This approach offers significant improvements for materials characterization and phase analysis.