Scanning Transmission Electron Microscopy-Atom Probe Tomography Correlative Analysis for the Characterization of...

Area of Science:

• Materials Science
• Metallurgy
• Nanotechnology

Background:

• Atom probe tomography (APT) and scanning transmission electron microscopy ((S)TEM) offer complementary atomic-scale insights.
• Correlative microscopy is crucial for understanding material microstructures.

Purpose of the Study:

• To investigate chromium segregation at dislocation loops in Fe-Cr alloys using correlative STEM/APT.
• To compare two distinct methods for correlative STEM/APT analysis.

Main Methods:

• Two correlative STEM/APT approaches were used: direct analysis on APT needles and iterative analysis on TEM lamellae.
• STEM identified dislocation loop Burgers vectors; APT reconstructed Cr segregation.
• The g•b = 0 invisibility criterion was adapted for STEM analysis of needle-shaped specimens.

Main Results:

• Both methods successfully identified Cr segregation at dislocation loops.
• Direct needle analysis offers straightforward correlation but limited volume.
• Lamellar analysis expands the observation area significantly but requires more steps.

Conclusions:

• Correlative STEM/APT is effective for studying solute segregation at defects.
• Method selection depends on the trade-off between observation volume and experimental complexity.
• Findings advance atomic-scale understanding of segregation phenomena in alloys.