| About this Abstract |
| Meeting |
2021 TMS Annual Meeting & Exhibition
|
| Symposium
|
Frontiers in Solidification Science VIII
|
| Presentation Title |
In-situ Measurement of Dendrite Tip Shape in a Metallic Alloy |
| Author(s) |
Christoph Beckermann, H. Neumann-Heyme, N. Shevchenko, J. Grenzer, S. Eckert |
| On-Site Speaker (Planned) |
Christoph Beckermann |
| Abstract Scope |
The size and shape of the primary dendrite tips determine the principal length scale of the microstructure evolving during solidification of alloys. In-situ measurements of the tip shape in metals have been unsuccessful so far due to insufficient spatial resolution or high image noise. Here we report on quantitative in-situ measurements of the geometry of dendrite tips in a thin sample of a directionally solidifying Ga-35wt.%In alloy. The measurements are based on a combination of high-resolution synchrotron radiography and advanced image processing techniques. Dendrite tips are observed during the fast initial transient and the subsequent steady growth period, with tip velocities ranging over almost two orders of magnitude. The dendrite tip shape selection parameter is measured to be σ≈0.075, suggesting a somewhat higher interface energy anisotropy than in aluminum alloys. The non-axisymmetric shape amplitude is found to be A_4≈0.004, which is in agreement with the universal value previously established. |
| Proceedings Inclusion? |
Planned: |