Correlating Grain Boundary Character and Composition in 3-Dimensions Using 4D-Scanning Precession Electron...

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Grain boundaries (GBs) are critical microstructural features in nanocrystalline materials.
• Solute segregation to GBs significantly impacts material stability and properties.
• GB character dictates the extent and location of solute segregation.

Purpose of the Study:

• To develop a 3D correlative framework for analyzing GB character and composition.
• To investigate the preferential segregation of Cu and Si in nanocrystalline Ni-W alloys.
• To achieve sub-nanometer resolution for structure-chemistry correlations.

Main Methods:

• Correlating 4D scanning precession electron diffraction tomography (4D-SPEDT) with atom probe tomography (APT).
• Utilizing a 3D transmission electron microscopy and APT framework.
• Analyzing the 3D grain boundary network and solute distribution.

Main Results:

• Obtained the 3D GB habit plane network in a nanocrystalline Ni-W alloy.
• Identified preferential segregation of Cu to high-angle and incoherent twin GBs.
• Observed Si segregation to low-angle and incommensurate GBs.

Conclusions:

• The developed 3D correlative approach enables high-resolution analysis of nanomaterials.
• Provides fundamental insights into the 3D crystallographic and compositional nature of GBs.
• Lays the groundwork for tailoring material properties through controlled solute segregation.