Detecting density variations and nanovoids.

Area of Science:

• Materials Science
• Nanotechnology
• Analytical Chemistry

Background:

• Atom probe tomography (APT) is a powerful technique for 3D atomic-scale chemical analysis.
• Detecting and characterizing nanoscale features like nanovoids is crucial for understanding material properties.
• Traditional methods may have limitations in resolving very small nanovoids.

Purpose of the Study:

• To determine the minimum size of nanovoids detectable using atom probe tomography.
• To evaluate the effectiveness of iso-density surfaces for nanovoid analysis in APT data.
• To explore the quantification of nanovoid characteristics and solute segregation.

Main Methods:

• Simulated APT data generation to establish detection limits.
• Application of iso-density surfaces to both simulated and experimental APT datasets.
• Analysis of an aluminum-yttrium-iron metallic glass ribbon using APT.
• Complementary use of field ion microscopy and thin section atom maps.

Main Results:

• Nanovoids as small as 1 nm in diameter are detectable with APT using iso-density surfaces.
• Iso-density surfaces enable quantification of nanovoid size, morphology, and number density.
• The approach was validated using experimental APT data from a metallic glass.
• Solute segregation to nanovoids can be investigated by combining iso-density surfaces with atom maps.

Conclusions:

• Iso-density surfaces are an effective method for detecting and quantifying nanovoids in APT data, down to the 1 nm scale.
• This technique enhances the characterization capabilities of APT for nanoscale defects and their associated chemistry.
• The findings have implications for materials characterization, particularly in metallic glasses and other nanostructured materials.