Thermodynamics of Interfaces: Theory to Atomistic Modeling

NONTECHNICAL SUMMARY

This award supports theoretical and computational research aimed at advancing the fundamental understanding of grain boundary thermodynamics and kinetics by atomistic computer modeling. Interfaces in crystalline materials play an essential role in many areas of science and technology. Almost all engineering materials contain internal interfaces separating crystalline domains (grains) with different crystallographic orientations.

These interfaces, called grain boundaries, often control the structural stability and properties of the material. For example, the solute elements in alloys often segregate to grain boundaries and make the alloy either stronger or catastrophically brittle. The design of new alloys heavily relies on the ability of researchers to understand and control grain boundary segregation and its effect on physical properties.

In this project, The PI will investigate the mechanisms of grain boundary segregation and grain boundary diffusion in Cu-Ag and Al-Mg alloy systems. The research will uncover key relationships between the thermodynamic (segregation) and kinetic (diffusion and migration) grain boundary properties. A diverse set of representative boundaries will be tested to demonstrate the generality of the results across different grain boundary types.

This project will impact several areas of materials science, physics, chemistry, and technology by expanding the fundamental knowledge of interface thermodynamics and kinetics, and by creating new capabilities for computational prediction of interface properties. To enhance the broader impacts, the PI will organize workshops and symposia on broad topics related to materials interfaces across different disciplines.

The PI and the students will also visit local high schools and give popular presentations featuring computational materials science with examples based on this project. When teaching graduate courses at Mason, the PI will utilize this research as a source of examples for lectures, homework assignments, and topics of term projects.

TECHNICAL SUMMARY

This award supports theoretical and computational research aimed at advancing the fundamental understanding of grain boundary thermodynamics and kinetics by atomistic computer modeling. Grain boundaries often control the structural stability, mechanical behavior, and physical properties of engineering materials. Specific goals of this project include: (1) Discover the fundamental mechanisms of grain boundary segregation and diffusion in alloys systems; (2) Investigate thermodynamics of grain boundary phase transformations; (3) Uncover relationships between the thermodynamic (segregation) and kinetic (diffusion) properties; (4) Investigate the solute drag effect by moving grain boundaries; and (5) Investigate the dynamic phase transformations in moving grain boundaries by direct molecular dynamics modeling.

The primary approach to achieving these goals is a tight integration of molecular dynamics, Monte Carlo simulations, and the jump correlation analysis. Cu-Ag and Al-Mg alloys will be chosen as model systems. A diverse set of representative grain boundaries will be tested to demonstrate the generality of the results.

This project will impact several areas of materials science, physics, chemistry, and technology by expanding the fundamental knowledge of interface thermodynamics and kinetics, and by creating new capabilities for computational prediction of interface properties. To enhance the broader impacts, the PI will organize workshops and symposia on broad topics related to materials interfaces across different disciplines.

The PI and the students will also visit local high schools and give popular presentations featuring computational materials science with examples based on this project. When teaching graduate courses at Mason, the PI will utilize this research as a source of examples for lectures, homework assignments, and topics of term projects.

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.