About this Abstract |
Meeting |
2020 TMS Annual Meeting & Exhibition
|
Symposium
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Materials Research in Reduced Gravity
|
Presentation Title |
Nucleation Fronts Growing in Al-Ni Melts Under Reduced Gravity |
Author(s) |
Marcus Reinartz, Stefan Burggraf, Matthias Kolbe, Peter Galenko, Dieter M. Herlach, Markus Rettenmayr |
On-Site Speaker (Planned) |
Markus Rettenmayr |
Abstract Scope |
Recent experiments were carried out using the Electromagnetic Levitator (EML) on board the International Space Station (ISS). Measurements of the dendrite growth velocity show an anomalous decrease with increasing undercooling and reproduce terrestrial results. However, the experiments identified a special growth mechanism in Al-rich Al-Ni melts. The growth front consists of numerous nuclei forming next to already existing solid and propagate along the sample surface. The growth of existing nuclei and the emergence of new nuclei are the driving forces for the front propagation. Initial analysis of the nucleation statistics including the number and the distance of the nuclei point at another unexpected behavior. Microstructure analyses support the hypothesis of surface nuclei by showing dendrites growing from the sample surface radially inwards. Yet, the question why the nuclei occur in these large numbers on the sample surface and drive the solidification is not yet answered and subject to further studies. |
Proceedings Inclusion? |
Planned: Publication Outside of TMS |