| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advanced Real Time Imaging
|
| Presentation Title |
In-situ Observation of Hyperbranched Dendrite Growth |
| Author(s) |
Tiberiu Stan, Kate Elder, Xianghui Xiao, Peter Voorhees |
| On-Site Speaker (Planned) |
Tiberiu Stan |
| Abstract Scope |
Many properties of structural alloys are largely controlled by the microstructures left behind after solidification. In-situ observation of dendrite growth in aluminum alloys is possible through synchrotron-based 4D x-ray computed tomography (XCT). The datasets are reconstructed using TIMBIR to achieve high spatial (0.55 micron) and temporal (0.25 second) resolutions, and segmented using a variety of convolutional neural network machine learning architectures. The time-resolved XCT studies of Al-Zn and Al-Zn-Cr alloys give insights into solidification processes over a range of timescales. Unlike classical dendrite morphologies, we show that the free-growing hyperbranched dendrites in Al-Zn alloys are approximately self-similar during growth. At longer time scales, changes in relative solid and liquid densities are observed, which lead to dendrite arm fragmentation and motion both with and against gravity. The resulting 4D experiments give new insights regarding the evolution of dendrite morphologies, tip radii, symmetries, crystallographic growth directions, and interfacial curvatures. |
| Proceedings Inclusion? |
Planned: |