Determining Grain Boundary Position and Geometry from EBSD Data: Limits of Accuracy

Area of Science:

• Materials Science
• Crystallography
• Electron Microscopy

Background:

• Accurate interpretation of geometrical sample information from electron backscatter diffraction (EBSD) data is crucial for nanoscale crystalline materials.
• The finite size of the excitation volume (EV) in EBSD can introduce errors in geometrical determination.

Purpose of the Study:

• To develop a method for accurately determining grain boundary (GB) geometry by accounting for the excitation volume (EV) in EBSD data.
• To compare different metrics from EBSD data as proxies for simulated backscattered electrons.
• To establish criteria for comparing experimental and simulated EBSD transition curves.

Main Methods:

• Utilizing transition curves from line scans across grain boundaries (GBs).
• Comparing various EBSD data metrics against Monte Carlo simulations of backscattered electrons.
• Deriving criteria for comparing experimental and simulated transition curves.

Main Results:

• Transition curves provide an accurate method for determining the sample surface GB position.
• Standard EBSD software may introduce significant errors in GB position determination.
• The excitation volume (EV) is generally too shallow to reveal subsurface GB geometry, such as inclination angle.

Conclusions:

• Accounting for the excitation volume (EV) using transition curves enhances the accuracy of grain boundary (GB) geometry determination from EBSD data.
• The study identifies limitations of standard EBSD software and provides a method for more precise GB positioning.
• Subsurface geometry, like GB inclination, cannot be reliably determined with this method due to the shallow EV.