Quantitative Understanding of Atomic Wear Using Accelerated Molecular Simulation

使用加速分子模拟定量理解原子磨损

• 批准号: 1031408
• 负责人: Yunfeng Shi
• 金额: $ 29.51万
• 依托单位: Rensselaer Polytechnic Institute
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-01 至 2014-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1031408&HistoricalAwards=false
• 关键词: Quantitative; Understanding; Atomic; Wear; Using

The goal of this proposed research is to develop a molecular-level understanding and a quantitative description of atomic wear during single-asperity sliding. Moving surfaces in contact can produce wear that shortens device lifetime and lowers energy efficiency. Molecular level simulations will be employed to understand how an amorphous silica tip blunts on a moving counter-surface under low loads. This simulation setup resembles the scanning of a silicon tip on polymer surfaces for high-density thermo-mechanical data storage, during which the native oxide layer of the silicon tip wears off. A novel accelerated molecular dynamics algorithm will be utilized to accelerate rare debris-generating events during sliding thus approach the experimental time scales. By simulating tip-sliding at various speeds, loads, contact areas and temperatures, the quantitative relation between the wear rate and loading conditions will be obtained. The applicability of the Archard's linear wear law and the nonlinear bond rupture model in the atomic wear regime will be critically evaluated.This research will enrich the fundamental knowledge on wear at the nanoscale, which is crucial for devising guidelines of operation conditions and estimating components lifetime for nanodevices with moving contacts, such as scanning probe-based memory storage, nanolithography as well as nano electromechanical systems. The computational platform developed here can also be used to investigate multi-asperity wear and tribochemical effects in the future. The educational components include outreach activities for high school students interested in science and engineering through the New Visions: Math, Engineering, Technology & Science (METS) program; curriculum development of a Modeling of Materials course at RPI; a continual effort on improving an open-source visualization software SimRePlay (www.simreplay.org) for the scientific community.

这项拟议研究的目标是从分子水平上理解和定量描述单凸体滑动过程中的原子磨损。接触时移动表面会产生磨损，从而缩短器件寿命并降低能效。分子水平的模拟将被用来理解无定形二氧化硅针尖在低负载下如何在移动的反表面上钝化。这种模拟设置类似于在高密度热机械数据存储的聚合物表面上扫描硅尖，在此期间硅尖的自然氧化层磨损。一种新的加速分子动力学算法将被用来加速滑动过程中罕见的碎片产生事件，从而接近实验时间尺度。通过模拟不同速度、载荷、接触面积和温度下的尖端滑动，得到磨损率与载荷条件之间的定量关系。对Archard的线性磨损定律和非线性键断裂模型在原子磨损区域的适用性进行了严格的评估，这项研究将丰富纳米级磨损的基础知识，这对于设计基于扫描探针的存储器存储、纳米光刻以及纳米机电系统等具有移动接触的纳米器件的操作条件指南和估计元件寿命至关重要。本文开发的计算平台还可用于研究多粗糙表面的磨损和摩擦化学效应。教育部分包括通过新视野：数学、工程、技术和科学(METS)方案为对科学和工程感兴趣的高中生开展外联活动；为RPI的材料建模课程编制课程；为科学界不断改进开源可视化软件SimRePlay(www.simreplay.org)。