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Evolution of dendritic patterns during alloy solidification: From the initial instability to the steady state
W Losert1, B Q Shi, H Z Cummins
1Department of Physics, City College of the City University of New York, New York, NY 10031, USA.
Summary
This study tracks crystal-melt interface evolution during alloy solidification. Researchers experimentally determined the time delay before pattern formation and compared coarsening dynamics to theoretical predictions, verifying initial instability
Area of Science:
- Materials Science
- Solidification Physics
- Crystallization
Background:
- Investigating crystal-melt interface evolution is crucial for understanding alloy solidification.
- The transition from planar to cellular and dendritic patterns is a key phenomenon.
Purpose of the Study:
- To experimentally determine the time delay between initial interface instability and observable pattern formation.
- To analyze interface morphology evolution from cellular to dendritic patterns.
- To compare measured coarsening dynamics with theoretical predictions.
Main Methods:
- Directional solidification of a dilute binary alloy.
- Experimental determination of critical time points (t(i) and t(0)).
- Analysis of interface morphology and coarsening dynamics.
Main Results:
- The time delay between marginal stability and observable pattern modulation was experimentally determined.
- The evolution from cellular to steady-state dendritic patterns was observed.
- Experimental data on coarsening dynamics were obtained and compared with theoretical models.
Conclusions:
- The initial instability plays a relevant role in steady-state pattern selection during solidification.
- Experimental measurements provide insights into the dynamics of pattern coarsening.