Three-dimensional full-field X-ray orientation microscopy.

Area of Science:

• Materials Science
• Crystallography
• Physics

Background:

• X-ray orientation microscopy (XOM) is a powerful technique for analyzing material microstructures.
• Existing methods like X-ray diffraction contrast tomography have limitations in resolving complex grain structures.

Purpose of the Study:

• To apply a novel mathematical framework for full-field X-ray orientation microscopy to experimental near-field diffraction data.
• To extend the applicability of X-ray diffraction imaging to materials with sub-grains and intra-granular orientation spreads.

Main Methods:

• Grain-by-grain tomographic reconstructions in six-dimensional position-orientation space using convex optimization.
• Derivation of 3D orientation maps from 6D reconstruction data and assembly into a common sample volume.
• Comparison of 3D orientation maps with Electron Backscatter Diffraction (EBSD) surface maps to quantify discrepancies.

Main Results:

• Successful application of the new framework to polycrystalline sample data, yielding 3D orientation maps.
• Quantification of local misorientations and grain boundary position discrepancies compared to EBSD.
• Demonstration of the method's ability to handle sub-grain and intra-granular orientation spreads up to a few degrees.

Conclusions:

• The new framework enhances X-ray diffraction imaging, enabling detailed characterization of complex material microstructures.
• The method allows for fast, isotropic 3D characterization and time-lapse observations of microstructural evolution.
• The approach bypasses traditional orientation indexation, working directly with experimental raw data.