Thermodynamics of Interfaces: Theory to Atomistic Modeling

非技术性总结该奖项支持旨在通过原子计算机建模推进晶界热力学和动力学基本理解的理论和计算研究。晶体材料中的界面在许多科学和技术领域中起着至关重要的作用。几乎所有的工程材料都含有内部界面，这些界面将具有不同结晶取向的晶域（晶粒）分开。这些界面称为晶界，通常控制材料的结构稳定性和性能。例如，合金中的溶质元素经常偏析到晶界，使合金变得更强或变得灾难性地脆。新合金的设计在很大程度上依赖于研究人员理解和控制晶界偏析及其对物理性能的影响的能力。在这个项目中，PI将研究Cu-Ag和Al-Mg合金系统中的晶界偏析和晶界扩散机制。这项研究将揭示热力学（偏析）和动力学（扩散和迁移）晶界性质之间的关键关系。一组不同的代表性边界将被测试，以证明在不同的晶界类型的结果的通用性。该项目将影响材料科学，物理，化学和技术的几个领域，通过扩展界面热力学和动力学的基础知识，并通过创建新的能力，计算预测界面性能。为了增强更广泛的影响，PI将组织研讨会和专题讨论会，讨论与不同学科材料界面相关的广泛主题。PI和学生们还将访问当地的高中，并以该项目为基础，以计算材料科学为主题进行流行的演讲。在梅森教授研究生课程时，PI将利用这项研究作为讲座，家庭作业和学期项目主题的例子来源。技术总结该奖项支持旨在通过原子计算机建模推进对晶界热力学和动力学的基本理解的理论和计算研究。晶界通常控制着工程材料的结构稳定性、力学行为和物理性能。本项目的具体目标包括：（1）揭示合金系晶界偏聚和扩散的基本机制;（2）研究晶界相变的热力学;（3）揭示晶界相变的热力学过程与合金系晶界相变的相互关系;（4）研究合金系晶界相变的热力学过程。（分离）和动力学（4）研究晶界运动对溶质的拖曳效应;（5）采用直接分子动力学模拟方法研究运动晶界的动态相变。实现这些目标的主要方法是分子动力学，蒙特卡罗模拟和跳跃相关分析的紧密结合。选择Cu-Ag和Al-Mg合金作为模型体系。将测试一组不同的代表性晶界，以证明结果的一般性。该项目将影响材料科学，物理，化学和技术的几个领域，通过扩展界面热力学和动力学的基础知识，并通过创建新的界面特性的计算预测能力。为了增强更广泛的影响，PI将组织研讨会和专题讨论会，讨论与不同学科材料界面相关的广泛主题。PI和学生们还将访问当地的高中，并以该项目为基础，以计算材料科学为主题进行流行的演讲。在梅森教授研究生课程时，PI将利用这项研究作为讲座，家庭作业和学期项目主题的例子来源。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

NONTECHNICAL SUMMARYThis 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 SUMMARYThis 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.