|About this Abstract
||2018 TMS Annual Meeting & Exhibition
||Frontiers in Solidification Science and Engineering
||Anomalous Dendrite Growth in Undercooled Al-Ni Melts
||Dieter Matthias Herlach, Marcus Reinartz, Peter K. Galenko, Markus Rettenmayr, Matthias Kolbe
|On-Site Speaker (Planned)
Metals and alloys show a dendrite growth velocity, V, which monotonically increases with undercooling ∆T. There are two exceptions: (i) glass forming systems with a high reduced glass temperature and (ii) Al-Ni alloys. The latter ones show a small reduced glass temperature which is far away from the temperature that can be reached by undercooling techniques. The effect of a negative slope in the V(∆T) relation cannot be explained by a rapid decrease of the atomic diffusion coefficient in the vicinity of the glass t temperature. In the present work experiments are presented on Al-Ni of the dendrite growth velocity as a function of undercooling measured both in microgravity and in the Earth laboratory. Various physical phenomena are discussed which may cause the anomalous growth in Al-Ni alloys: Forced convection, phase selection and special characteristic features of thermodynamics.
||Planned: Supplemental Proceedings volume