CAREER: Microstructure-Property Relationships in Carbon-Based Nanostructures

该职业奖支持理论研究，以阐明微观结构在决定界面材料性能中的作用，并支持教育活动，包括将各种材料建模组件引入材料科学和工程课程，开发多媒体和可视化教学工具，以及推广K-12教育活动。通过对金刚石界面和纳米金刚石模型体系的研究，重点研究脆性界面材料的力学性能。界面脆性材料的力学性能研究将集中于分析微结构和环境效应在脆性断裂中的作用，特别强调将原子模拟与断裂力学的大量知识联系起来。它的纯脆性及其在各种应用中的潜力，如开发微型和纳米机电系统所需的应用，促使人们选择纳米晶体钻石，这是一种模型脆性材料。PI将使用原子模拟来解决以下问题：(I)脆性裂纹的扩展主要由平衡热力学控制，还是由动力学控制？(2)微结构对裂纹的扩展、偏转和止裂有什么影响？(3)温度和环境对骨折有什么影响？为了探索广泛的微观结构并提供对碳-氢系统的高度可靠的描述，原子模拟将与紧束缚模拟相结合。模拟结果将与界面材料力学的连续介质有限元模拟方法的结果进行比较。教育活动将侧重于开发材料理论和建模课程，并将以讲授为基础的课程在本科生和研究生一级转变为互动形式。教育活动的一个关键方面将是通过与实验者合作开发课程，使学生接触到建模和实验的互补性质。各种多媒体工具和网络资源将被整合到教学中，以帮助实现这一目标。将探索跨大学网络辅助教学，以扩大工程课程的保留范围。还将开发与平台无关的、开源的交互式软件，用于分子和其他物理过程的可视化。这个课程和教育软件最终将与材料科学界共享。教育部分还包括一个让K-12学生接触材料科学和材料科学职业选择的外展计划。这个职业奖项支持理论研究和教育。建议的研究重点是利用模拟来阐明材料的微观结构在决定其力学性能方面的作用。通过对金刚石界面和纳米金刚石模型系统的研究，将两种不同的模拟方法结合起来，在不同的长度尺度上精确地描述脆性界面材料的脆性断裂。该提案的教育部分涉及通过课程开发和重组将材料建模和模拟引入材料科学和工程课程，并涉及为教学开发新的模拟和可视化软件工具，将与材料科学界分享。教育部分还包括一个让K-12学生接触材料科学和材料科学职业选择的外展计划。

This CAREER award supports theoretical research to elucidate the role of microstructure in determining the properties of interfacial materials and supports education activities that involve introducing various materials modeling components to the materials science and engineering curriculum, development of multimedia and visual teaching tools, and outreach to K-12 educational activities. Research will focus on mechanical properties of brittle interfacial materials through the study of diamond interfaces and nanocrystalline diamond model systems. Studies of mechanical properties of interfacial brittle materials will focus on analyzing the role of microstructure and environmental effects in brittle fracture with particular emphasis on relating atomistic simulations to the large body of knowledge on fracture mechanics. Its purely brittle nature and its potential for various applications such those needed for developing micro- and nano-electromechanical systems motivate the choice of nanocrystalline diamond, a model brittle material. The PI will use atomistic simulations to address the questions: (i) Is brittle crack propagation governed mainly by equilibrium thermodynamics or is it dominated by kinetics? (ii) What are the effects of microstructure on crack propagation, deflection and arrest? (iii) What are effects of temperature and environment on fracture? In order to explore a wide range of microstructures and provide a highly reliable description of carbon-hydrogen systems, atomistic simulations will be combined with tight-binding simulations. Simulation results will be compared with those from continuum finite element modeling approaches to the mechanics of interfacial materials. Educational activities will focus on developing courses on materials theory and modeling, and on restructuring lecture-based coursework into an interactive format at both the undergraduate and graduate levels. A key aspect of educational activities will be to expose students to the complementary nature of modeling and experiment by developing coursework in collaboration with experimentalists. A variety of multimedia tools and web resources will be integrated into teaching to assist in achieving this objective. Cross-university web-assisted teaching will be explored in order to broaden the repertoire of the engineering curriculum. Platform independent, open source and interactive software for visualization of molecular and other physical processes will also be developed. This courseware and educational software will ultimately be shared with the materials science community. The educational component also includes an outreach program to expose K-12 students to materials science and materials science career options.This CAREER award supports theoretical research and education. The proposed research focuses on using simulation to elucidate the role of the microsctructure of materials in determining their mechanical properties. A simulation approach that couples two different simulation methods that are accurate on different length scales will be used to provide an atomistic description of brittle fracture in brittle interfacial materials through the study of diamond interfaces and nanocrystalline diamond model systems. The educational component of the proposal involves introducing materials modeling and simulation into the materials science and engineering curriculum through course development and restructuring, and involves developing new simulation and visualization software tools for teaching which will be shared with the materials science community. The educational component also includes an outreach program to expose K-12 students to materials science and materials science career options.