A Peierls Perspective on Mechanisms of Atomic Friction

佩尔斯对原子摩擦机制的看法

• 批准号: 0900027
• 负责人: Yanfei Gao
• 金额: $ 19.8万
• 依托单位: University of Tennessee Knoxville
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2014-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0900027&HistoricalAwards=false
• 关键词: Peierls; Perspective; Mechanisms; Atomic; Friction

The objective of this research is to develop a Peierls perspective on the atomic-friction mechanisms from the spatiotemporal evolution of interface defect structures. Despite a quantitative experimental capability of examining nanoscale frictional behavior, existing modeling efforts, such as Tomlinson-type models or molecular simulations, are still unable to quantitatively explain the effects of lattice incommensurability, rate- and temperature-dependence, etc. A Peierls-type framework will be established to replace singular defect model by the inhomogeneous slip field on the interface. Experimental observations, such as structural lubricity, frictional anisotropy, and contact size dependence, can be explained as a consequence of initiation and multiplication of interface dislocations and their interactions with pre-existing interface defects. From the kinetics standpoint, the proposed work will examine the spatially inhomogeneous nature of the rate-determining process, accurately calculate the activation energy with respect to the interface defects, and thus explain the thermally activated frictional behavior.The uniqueness of the proposed work, as compared to a vast literature in this field, is the ability to quantitatively predict the atomic processes that govern the spatiotemporal evolution of the interface defects during friction. This viewpoint enables quantitative experimental comparisons and resolves drawbacks and difficulties of existing modeling efforts. It will open a broad door for both undergraduate and graduate students to participate in a multi-disciplinary education/research environment, and thus advances and enhances focused research and education activities in the PI?s institute. The PI will develop new instructional materials and hands-on computational demonstrations for incorporation into a variety of outreach and diversity programs, and thus promote the interests of high school and college students in science and engineering careers, as well as the engagement of public awareness.

本研究的目的是从界面缺陷结构的时空演化角度发展对原子摩擦机制的 Peierls 视角。尽管具有检查纳米级摩擦行为的定量实验能力，但现有的建模工作，例如汤姆林森型模型或分子模拟，仍然无法定量解释晶格不可通约性、速率和温度依赖性等的影响。将建立框架，用界面上的非均匀滑移场代替奇异缺陷模型。实验观察结果，例如结构润滑性、摩擦各向异性和接触尺寸依赖性，可以解释为界面位错的引发和倍增及其与预先存在的界面缺陷相互作用的结果。从动力学的角度来看，该工作将检查速率决定过程的空间不均匀性质，准确计算界面缺陷的活化能，从而解释热激活摩擦行为。该工作的独特性在于与该领域的大量文献相比，定量预测控制摩擦过程中界面缺陷时空演化的原子过程的能力。这种观点可以进行定量实验比较，并解决现有建模工作的缺点和困难。它将为本科生和研究生参与多学科教育/研究环境打开一扇大门，从而推进和加强 PI 研究所的重点研究和教育活动。 PI 将开发新的教学材料和动手计算演示，以纳入各种外展和多样性计划，从而提高高中生和大学生对科学和工程职业的兴趣以及公众意识的参与。