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Interface kinetics in phase-field models: isothermal transformations in binary alloys and step dynamics in
1Computational Materials Design Department, Max-Planck Institut für Eisenforschung, D-40237 Düsseldorf, Germany and Peter Grünberg Institut, Forschungszentrum Jülich, D-52425 Jülich, Germany.
Physical Review. E, Statistical, Nonlinear, and Soft Matter Physics
|September 17, 2013
Summary
This study introduces a unified model for interface kinetics in phase-field modeling, enhancing accuracy for binary alloys and epitaxy. The new model incorporates cross-coupling effects, improving predictions for phenomena like step-bunching instability.
Area of Science:
- Materials Science
- Computational Physics
- Chemical Engineering
Background:
- Classical phase-field models often omit kinetic cross-coupling effects between phase and concentration fields.
- Understanding interface kinetics is crucial for accurately simulating material transformations and growth processes.
Purpose of the Study:
- To present a unified description of interface kinetic effects in phase-field models.
- To incorporate generalized kinetic cross-coupling for improved accuracy in binary alloy transformations and molecular-beam epitaxy.
- To derive general expressions for kinetic coefficients using a simplified reduction procedure.
Main Methods:
- Developed phase-field equations of motion with kinetic cross-coupling.
- Employed a physically motivated reduction procedure, equivalent to the thin-interface limit, to derive kinetic coefficients.
- Performed numerical simulations of step-bunching instability in molecular-beam epitaxy.
Main Results:
- Derived general, model-independent expressions for kinetic coefficients.
- Demonstrated the possibility of a nonpositive definite matrix of kinetic coefficients, indicating negative effective interface dissipation within stable regimes.
- Successfully reproduced step-bunching instability due to the Ehrlich-Schwoebel effect via cross-coupling.
Conclusions:
- The unified phase-field model with cross-coupling provides a more comprehensive description of interface kinetics.
- The simplified reduction procedure offers a computationally efficient alternative to the thin-interface limit.
- The model accurately captures complex phenomena like step-bunching instability, validating its predictive power.
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