Experimentally-validated multi-slice simulation of electron diffraction patterns

Area of Science:

• Materials Science
• Crystallography
• Computational Physics

Background:

• High-Resolution Electron Backscatter Diffraction (HR-EBSD) enables submicron elastic strain and dislocation density measurements.
• Accurate HR-EBSD analysis relies on matching experimental patterns with high-quality simulated dynamical patterns.
• Current Bloch Wave (BW) simulations are limited to perfect crystal structures, while Multi-Slice (MS) simulations, though capable of handling defects, lack experimental validation.

Purpose of the Study:

• To optimize the Multi-Slice (MS) method for simulating High-Resolution Electron Backscatter Diffraction (HR-EBSD) patterns.
• To validate the optimized MS method by comparing simulation results with experimental HR-EBSD data.
• To enhance the precision and applicability of MS simulations for materials with complex microstructures and defects.

Main Methods:

• Optimized the MS method by abandoning the high-energy approximation and employing higher-order Taylor expansions for the Schrödinger equation.
• Implemented a 5th-order expansion of MS (MS5) to balance computational efficiency and pattern accuracy.
• Utilized experimental EBSD patterns from polycrystal Al-Mg alloys for validation and incorporated a distortion correction model and stereographic triangle reconstruction.

Main Results:

• The optimized MS method (MS5) demonstrates a good balance between computational cost and pattern precision.
• MS5 simulations show comparable precision to the Bloch Wave (BW) method after incorporating correction models.
• This study presents the first comparison of MS EBSD simulations with experimental data, validating its capability.

Conclusions:

• The optimized MS method provides a viable alternative for HR-EBSD pattern simulation, especially for materials containing defects.
• This advancement opens new avenues for HR-EBSD characterization, including the simulation of diffraction patterns from crystals with various defects.
• The validated MS approach enhances the accuracy and scope of electron diffraction analysis in materials science.