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Methods of Ex Situ and In Situ Investigations of Structural Transformations: The Case of Crystallization of Metallic Glasses
Published on: June 7, 2018
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Temperature and initial composition dependence of pattern formation and dynamic behavior in phase separation under
Liang Zhang1, Yinli Peng1, Li Zhang2
1MOE Key Laboratory of Materials Physics and Chemistry under Extraordinary Conditions, School of Natural and Applied Sciences, Northwestern Polytechnical University Xi'an 710072 China nan.wang@nwpu.edu.cn.
RSC Advances
|May 6, 2022
Summary
Simulating phase separation in succinonitrile-water solutions reveals temperature and composition significantly impact structure. Lower temperatures and compositions near critical values yield finer, droplet-like structures and faster separation.
Area of Science:
- Materials Science
- Physical Chemistry
- Computational Modeling
Background:
- Phase separation is a critical phenomenon in liquid mixtures, influencing material properties.
- Understanding the dynamics of phase separation is essential for controlling material morphology.
- Succinonitrile-water (SCN-H2O) mixtures serve as a model system for studying liquid-liquid phase separation.
Purpose of the Study:
- To investigate the effects of quenching temperature and initial composition on SCN-H2O phase separation patterns.
- To analyze the dynamic behavior of the second phase during spinodal decomposition and nucleation-driven growth.
- To examine the influence of thermodynamic parameters on domain growth laws and spatial morphology.
Main Methods:
- Two-dimensional simulations of SCN-H2O phase separation using Model H.
- CALPHAD (Calculation of Phase Diagrams) approach to determine molar free energy.
- Analysis of pattern formation and dynamics using Minkowski functionals.
Main Results:
- Temperature and composition do not alter the exponent in the domain growth law (R(t) ~ t^n).
- Lower temperatures promote finer bicontinuous structures and accelerate phase separation via increased nucleation.
- Initial composition influences spatial patterns, shifting from bicontinuous to droplet-like structures as it diverges from critical composition.
Conclusions:
- Quenching temperature and initial composition are key factors in controlling SCN-H2O phase separation morphology and kinetics.
- Lower temperatures and compositions closer to critical values lead to smaller, more numerous droplets.
- The interplay between spinodal decomposition and nucleation governs the final microstructure and separation rate.
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