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Updated: Dec 30, 2025
08:55
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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Revisiting the Stokes-Einstein relation for glass-forming melts.
Qi-Long Cao1, Pan-Pan Wang, Duo-Hui Huang
1Key Laboratory of Computational Physics, Yibin University, Yibin 644007, P. R. China. qlcao@mail.ustc.edu.cn.
Physical Chemistry Chemical Physics : PCCP
|January 17, 2020
Summary
Molecular dynamics simulations reveal that the Stokes-Einstein relation breakdown temperature (TSE) is approximately twice the glass-transition temperature (Tg) for metallic glasses. This finding aids in predicting the relation
Area of Science:
- Materials Science
- Computational Materials Science
- Condensed Matter Physics
Background:
- The Stokes-Einstein (SE) relation connects diffusion and viscosity in materials.
- Understanding its validity in glass-forming melts is crucial for materials design.
- Previous studies have explored SE relation in various systems with mixed results.
Purpose of the Study:
- To investigate the validity and breakdown of the Stokes-Einstein relation in metallic glass-forming melts.
- To determine the relationship between the SE breakdown temperature (TSE), dynamical crossover temperature (TA), and glass-transition temperature (Tg).
- To explore the underlying mechanisms for the decoupling of component diffusion coefficients.
Main Methods:
- Performed molecular dynamics simulations for Ni36Zr64, Cu65Zr35, and Ni80Al20 metallic glass melts.
- Simulations covered a wide temperature range (900–3000 K).
- Analyzed self-diffusion coefficients, viscosity, and partial pair structural correlations.
Main Results:
- Established TSE = TA ≈ 2.0Tg for the studied glass-forming melts.
- Observed that the product of self-diffusion coefficient and viscosity (Dαη) is constant near TSE.
- Identified decoupling of component diffusion coefficients below TSE, linked to partial pair structural decoupling.
Conclusions:
- The Stokes-Einstein relation breaks down at a predictable temperature (TSE ≈ 2.0Tg).
- The ratio of partial pair correlation entropy can predict SE relation validity without transport data.
- Findings provide insights into the dynamics and structure of metallic glass melts.
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