Clustering and local magnification effects in atom probe tomography: a statistical approach

Area of Science:

• Materials Science
• Analytical Chemistry
• Nanotechnology

Background:

• Quantitative composition analysis in three-dimensional atom probe tomography (3D APT) faces challenges.
• Local magnification effects and trajectory overlaps, especially around solute-enriched clusters, bias compositional data.
• Accurate assessment of tiny clusters remains an open issue in 3D APT.

Purpose of the Study:

• To develop a model for correcting biased compositional data in 3D APT reconstructions.
• To address local magnification effects and trajectory overlaps caused by second-phase clusters.
• To improve the accuracy of quantitative composition analysis for small, solute-enriched clusters.

Main Methods:

• A novel model was developed based on the distribution of distances between first nearest neighbor atoms.
• The model quantifies variations in apparent atomic density within reconstructed volumes.
• The method was applied to both simulated and experimental 3D APT data.

Main Results:

• The developed model effectively exhibits variations in apparent atomic density.
• It successfully corrects compositions biased by local magnification effects.
• Excellent agreement was observed between the model's corrected compositions and expected cluster compositions.

Conclusions:

• The nearest neighbor distance model provides a robust solution for local magnification effects in 3D APT.
• This approach enhances the accuracy of quantitative composition analysis, particularly for nanoscale clusters.
• The findings offer a significant improvement for materials characterization using 3D APT.