Grain size measurement by EBSD in complex hot deformed metal alloy microstructures

Area of Science:

• Materials Science
• Metallurgy
• Microscopy

Background:

• Accurate microstructure quantification is vital for understanding material properties.
• Hot deformed metal alloys often exhibit wide grain size distributions.
• Electron Backscatter Diffraction (EBSD) is a powerful technique for microstructural analysis.

Purpose of the Study:

• To investigate the accuracy of grain size measurement using EBSD in hot deformed metal alloys.
• To assess the impact of EBSD step size and noise reduction on grain size quantification.
• To compare EBSD grain size measurements with traditional optical methods.

Main Methods:

• Utilizing Electron Backscatter Diffraction (EBSD) for microstructural analysis.
• Systematically varying EBSD step size (5% to 20% of mean grain size).
• Applying standard noise reduction techniques during EBSD data processing.

Main Results:

• Increasing EBSD step size by 15% altered arithmetic mean grain size by ~15%.
• Standard noise reduction techniques introduced up to 20% variation in reported grain size.
• Grain size distribution was non-log-normal, featuring a tail of smaller grains.
• EBSD revealed up to 50% difference compared to optical methods due to twin distinction and smaller grain resolution.

Conclusions:

• EBSD provides more representative grain size quantification for hot deformed alloys than optical methods.
• Optimizing EBSD step size and noise reduction is essential for accurate microstructure analysis.
• The non-log-normal grain size distribution highlights the complexity of deformed microstructures.