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Spinodal decomposition and droplets entrapment in monotectic solidification
F Wang1, A Choudhury, C Strassacker
1Institute of Materials and Processes, Karlsruhe University of Applied Sciences, Moltkestrasse 30, 76133 Karlsruhe, Germany.
The Journal of Chemical Physics
|July 27, 2012
Summary
This study introduces two models for simulating solidification in monotectic alloys. The second model successfully simulates larger scales, revealing how surface energy and undercooling impact dynamic entrapment during monotectic reactions.
Area of Science:
- Materials Science
- Computational Materials Science
Background:
- Monotectic alloys exhibit complex solidification morphologies.
- Simulating these morphologies requires accurate models that can handle phase separation and interfacial phenomena.
Purpose of the Study:
- To present two distinct phase-field models for simulating solidification morphologies in monotectic alloys.
- To investigate morphological evolution influenced by spinodal decomposition using a nanometer-scale model.
- To develop and apply a second model for simulating larger scales, focusing on the dynamic entrapment process in monotectic reactions.
Main Methods:
- The first model incorporates a gradient energy contribution to stabilize phase separation within the miscibility gap, using bulk energy density interpolation.
- The second model excludes concentration gradient contributions for larger-scale simulations, adapting existing phase-field approaches.
- The second model was employed to simulate the dynamic entrapment process, analyzing the effects of liquid-liquid surface energy and undercooling.
Main Results:
- The first model is limited to nanometer scales due to surface excess contributions.
- The second model allows for larger-scale simulations with higher interface widths by eliminating equilibrium free energy excess across the interface.
- Simulations using the second model demonstrated the influence of liquid(1)-liquid(2) surface energy and undercooling on the dynamic entrapment process.
Conclusions:
- Two phase-field models were developed for monotectic alloy solidification.
- The second model offers advantages for larger-scale simulations and studying dynamic processes like entrapment.
- Surface energy and undercooling are critical parameters influencing dynamic entrapment in monotectic reactions.
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