About this Abstract |
Meeting |
2024 TMS Annual Meeting & Exhibition
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Symposium
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Advanced Characterization Techniques for Quantifying and Modeling Deformation
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Presentation Title |
Imaging Ghosts with 4D-STEM: Diffuse Scattering, Vacancies and Vanishing Dislocations |
Author(s) |
Sean Mills, Yang Yang, Jenn Donohue, Andrew M. Minor |
On-Site Speaker (Planned) |
Andrew M. Minor |
Abstract Scope |
This talk will demonstrate our application of 4D-STEM to map nanostructural features in materials relevant for understanding deformation mechanisms. For instance, we can map the nanoscale strain and phase landscape during in situ cooling of a NiTi through the phase transformation from the high temperature B2 cubic austenite phase to the low temperature B19’ monoclinic martensite phase.
4D-STEM also provides an opportunity to map vacancy distributions with nanoscale resolution. Our experiments using a model Au film demonstrates the 4D-STEM method for measuring vacancy concentration by closely following the differential thermal expansion method to measure the concentrations of point defects. Lastly, this talk will also describe our recent results utilizing in situ 4D-STEM during nanomechanical testing to provide insight into multiscale deformation phenomena in CrCoNi. 4D-STEM can provide both real-space imaging and diffraction analysis during in situ testing, making it possible to classify defects during in situ deformation before they disappear. |
Proceedings Inclusion? |
Planned: |
Keywords |
Characterization, High-Entropy Alloys, Phase Transformations |