About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
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| Symposium
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Four-Dimensional Scanning Transmission Electron Microscopy (4D STEM) for Quantitative Materials Characterization
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| Presentation Title |
In situ 5D STEM of Metallic Liquids and Their Crystallization |
| Author(s) |
Scott Dahl, Po-Cheng Kung, Paul Voyles |
| On-Site Speaker (Planned) |
Paul Voyles |
| Abstract Scope |
Direct electron detectors capable of acquiring a diffraction pattern in ~10 microseconds make in situ 5D STEM experiments practical. In 5D STEM, the probe is repeatedly rastered across the sample to generate 4D STEM data as a function of a time. We have used 5D STEM to study the dynamics and crystallization of metallic liquids. We have demonstrated nanometer-resolution images of phenomena including spatially heterogeneous dynamics and dynamic facilitation in supercooled liquids and used those data to quantify behavior for comparison to theory. We have also discovered a two-step crystallization process for a Pd-Cu-Si liquid and measured its kinetics. Step one is formation from the liquid of a nanometer-scale precursor state with more order than the liquid but less order than the crystal. Step two is crystallization from inside the precursor. The thermal activation energy for precursor formation is higher than the activation energy for crystallization from the precursor. |
| Proceedings Inclusion? |
Planned: |