Methods for orientation and phase identification of nano-sized embedded secondary phase particles by 4D scanning...

Area of Science:

• Materials Science
• Crystallography
• Electron Microscopy

Background:

• Transmission electron microscopy (TEM) diffraction patterns superimpose reflections from overlapping crystallites.
• This superimposition complicates automated orientation and phase mapping, especially for secondary phase particles within a matrix.

Purpose of the Study:

• To describe numerical approaches for overcoming diffraction pattern superimposition in 4D scanning precession electron diffraction (4D-SPED) data.
• To enable accurate phase and orientation mapping in complex microstructures.

Main Methods:

• Developing numerical strategies to emphasize secondary particle signatures.
• Implementing methods to subtract dominant matrix diffraction information.
• Applying these techniques to 4D-SPED datasets.

Main Results:

• Successfully applied numerical methods to steel samples with precipitates in Burgers orientation relationship.
• Demonstrated effectiveness on an aluminum alloy containing randomly oriented Mn-rich particles.
• Validated the ability to distinguish and map secondary phases despite matrix superimposition.

Conclusions:

• The described numerical approaches effectively resolve diffraction pattern superimposition issues in 4D-SPED.
• These methods significantly enhance automated analysis for materials containing embedded secondary phases.
• Facilitates detailed microstructural characterization in complex alloys.