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Defining clusters in APT reconstructions of ODS steels
Ceri A Williams1, Daniel Haley, Emmanuelle A Marquis
1Department of Materials, University of Oxford, Parks Road, Oxford OX1 3PH, UK.
Ultramicroscopy
|January 22, 2013
Summary
Investigating oxide nanoclusters in ODS steel using atom probe tomography revealed that direct comparison between alloy powder and consolidated material is challenging. A new method optimizes parameters for reliable quantification of nanocluster differences.
Area of Science:
- Materials Science
- Metallurgy
- Nanotechnology
Background:
- Oxide dispersion strengthened (ODS) steels are advanced alloys for high-temperature applications.
- Atom probe tomography (APT) is crucial for characterizing nanoscale features in materials.
Purpose of the Study:
- To investigate and compare oxide nanoclusters in Fe-14Cr-2W-0.3Ti-0.3Y₂O₃ ODS steel powder and its consolidated form.
- To develop a reliable method for quantifying differences in nanoclusters between the two states.
Main Methods:
- Atom probe tomography (APT) was used to analyze oxide nanoclusters.
- The maximum separation method was employed for cluster characterization.
- A parameter optimization procedure was developed by sweeping d(max) and N(min) values.
- A matrix correction was applied to account for trajectory aberrations.
Main Results:
- Direct comparison of nanoclusters using standard APT methods is not feasible due to differing clustering extents.
- Optimized cluster selection parameters and matrix correction enable reliable quantification of nanocluster differences.
- The study highlights the significant impact of parameter selection on cluster size and composition.
Conclusions:
- A robust methodology was established for accurately comparing oxide nanoclusters in different material states.
- This approach ensures reliable quantification of nanocluster evolution during ODS steel processing.
- The findings are critical for understanding and optimizing ODS steel performance.
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