Simulation and Theory of Solid-Liquid Interfaces and Grain Boundaries

固液界面和晶界的模拟和理论

• 批准号: 0957102
• 负责人: Brian Laird
• 金额: $ 43.5万
• 依托单位: University of Kansas Center for Research Inc
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-03-01 至 2014-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0957102&HistoricalAwards=false
• 关键词: Simulation; Theory; Solid; Liquid; Interfaces

Brian Laird of the University of Kansas is supported by an award from the Theory, Models and Computational Methods program. The project focuses on understanding the role that atomic and molecular interactions play in shaping thermodynamic and kinetic properties of solid-liquid and solid-solid interfaces. This effort requires development, evaluation and application of new computational methods. The proposed methodology is a mixture of fundamental studies of interfaces using model potentials with studies of realistic materials. Reliable experimental results of interfacial phenomena are challenging and rare. Thus, atomistic simulation is an important means for determining the thermodynamic phenomenology of such processes.The thermodynamics and growth kinetics of interfaces in condensed matter systems are primarily controlled by two quantities: the interfacial free energy and the kinetic coefficient. The interfacial free energy between two coexisting phases is the amount of work required to reversibly form a unit area of interface. The kinetic coefficient is the constant of proportionality between the growth velocity of an advancing interface and the undercooling drop in temperature. Accurate values of both are necessary for the full understanding of phenomena such as dendritic crystal growth, crystal nucleation, wetting, liquid-metal embrittlement, and others. Specific tasks that will be addressed are: (i) new method to quantify the dependence of the interfacial free energy on atomic and molecular interactions, (ii) direct method development to calculate grain boundary free energies, (iii) method adaptation to study the interface thermodynamics and structure of chemically heterogeneous solid-liquid interfaces; (iv) method for detecting the dependence of the kinetic coefficient on intermolecular forces, and (v) method to calculate the interfacial free energy of molecular systems, including binary mixtures.Broader impacts include continued participation in a cooperative research team on Dynamics and Cohesion of Materials Interfaces encompassing semiannual collaborative meetings between materials scientists, chemists and physicists. Efforts for training of students in the techniques of computational chemistry, programming and modeling will be undertaken within the Chemistry NSF-funded REU program at Kansas University, which has a strong history of participation by underrepresented groups.

堪萨斯大学的布莱恩·莱尔德得到了理论、模型和计算方法项目的支持。该项目的重点是理解原子和分子相互作用在形成固-液和固-固界面的热力学和动力学性质中的作用。这项工作需要开发、评估和应用新的计算方法。所提出的方法是一个混合物的基本研究接口使用模型的潜力与现实材料的研究。可靠的界面现象的实验结果是具有挑战性的和罕见的。因此，原子模拟是确定这类过程热力学现象的重要手段。凝聚态系统中界面的热力学和生长动力学主要由两个量控制：界面自由能和动力学系数。两个共存相之间的界面自由能是可逆地形成单位面积界面所需的功的量。动力学系数是前进界面的生长速度与过冷温度下降之间的比例常数。 两者的精确值对于充分理解诸如枝晶生长、晶体成核、润湿、液态金属脆化等现象是必要的。具体的任务是：（i）新的方法来量化的原子和分子相互作用的界面自由能的依赖，（ii）直接方法的发展，计算晶界自由能，（iii）方法适应研究界面热力学和结构的化学不均匀的固-液界面;（iv）检测动力学系数对分子间力的依赖性的方法，和（v）计算分子系统的界面自由能的方法，更广泛的影响包括继续参加关于材料界面动力学和凝聚力的合作研究小组，其中包括材料科学家、化学家和物理学家每半年举行一次的合作会议。在计算化学，编程和建模技术的学生培训的努力将在化学NSF资助的REU计划在堪萨斯大学，其中有一个由代表性不足的群体参与的强大的历史进行。