| About this Abstract |
| Meeting |
2023 TMS Annual Meeting & Exhibition
|
| Symposium
|
Materials Research in Reduced Gravity
|
| Presentation Title |
Nucleation and Growth Dynamics of Equiaxed Dendrites in Thin Metallic Samples in Microgravity and on Ground |
| Author(s) |
Maike Becker, Mareike Wegener, Jörg Drescher, Florian Kargl |
| On-Site Speaker (Planned) |
Maike Becker |
| Abstract Scope |
In situ X-radiography observations of the solidification of binary metallic alloys give valuable insights into the development of the microstructure. In this study, the nucleation and growth characteristics of equiaxed dendrites in near-isothermal solidification experiments, performed during two sounding rocket missions, MAPHEUS-6 and 7, are presented. Samples of the composition Al-15 wt.%Cu and Al-46 wt.%Ge were processed in microgravity and several samples on ground. The measured dendritic growth rates and observed concentration distributions in the liquid indicate no difference between microgravity and on-ground horizontal solidification experiments in line with previous observations. On the contrary, a difference in the nucleation behavior was found. In all microgravity experiments bursts of nucleation were observed, which is different from comparable on-ground experiments, where nucleation occurs continuously. The findings suggest that small convective flows still present in thin samples affect nucleation undercooling resulting in different nucleation behavior on Earth and in microgravity. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Solidification, Aluminum, Characterization |