Understanding Grain Boundary Multiplicity and Its Role in Deformation Mechanisms of Nanocrystalline Metals

了解晶界多重性及其在纳米晶金属变形机制中的作用

• 批准号: 2105328
• 负责人: Penghui Cao
• 金额: $ 46.74万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-07-01 至 2024-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2105328&HistoricalAwards=false
• 关键词: Understanding; Grain; Boundary; Multiplicity; Its

NON-TECHNICAL SUMMARYA grain is a crystallite where the atoms are periodically arranged. The interface between differently oriented grains, i.e., grain boundaries, strongly influences, if not determine, many mechanical and physical properties of materials, such as strength, ductility (material’s ability to bend before breaking), and resistance to radiation damage. Increasing scientific data suggests that grain boundaries in metals can have many different kinds of atomic arrangements (also known as multiplicity), and the transition between them leads to significant property changes. If we have a better understanding of grain boundary multiplicity and its structure-property relationship, scientists and engineers can devise synthesis strategies to tailor grain boundaries towards enhanced mechanical performance of nanostructured metals. In this project, Dr. Penghui Cao and Dr. Huolin Xin at UC Irvine will use forefront computational modeling and electron microscopy tools to study grain boundary multiplicity at the atomic level and reveal its critical role in determining how nanocrystalline metals deform. A fundamental understanding of grain boundary multiplicity could facilitate the design of engineering metals with desirable mechanical properties for structural applications, such as aerospace and nuclear energy systems. The project-based education plan aims to attract the participation of high school students from diverse backgrounds and thereby motivate and enable underrepresented minorities to pursue STEM careers.TECHNICAL SUMMARYThis project centers on revealing the 3D atomic structure of grain boundaries and fundamentally understanding how grain boundary structure multiplicity influences plastic deformation mechanisms of nanostructured metals. Scientifically, we hypothesize that the plastic deformation mechanisms in nanocrystalline metals can be tuned by tailoring grain boundary multiplicity. To test this central hypothesis, we propose research tasks combining atomistic simulation, reaction pathway simulations, theoretical modeling, electron tomography, and in-situ transmission electron microscopy experiments. This integrated computational and experimental study aims to address four major questions: (1) How to determine the 3D atomic structure of grain boundaries, revealing boundary defects, structure units, and multiplicity? (2) How do grain boundary defects and multiplicity influence mobility and migration mechanisms of grain boundaries? (3) Is it possible to control plastic deformation by tailoring grain boundary state and structure multiplicity, which results in enhanced plasticity and ductility in nanocrystalline metals? (4) What are the new deformation mechanisms which can be enabled by defective grain boundary or transformed boundary? The physical insights gained from this research will advance the exploitation of structure-property relationships in nanostructured metals, laying the groundwork for effective tailoring of mechanical behaviors through controlling structure, multiplicity, crystallographic distribution of boundaries.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.

非技术概述晶粒是原子周期性排列的微晶。不同取向的晶粒之间的界面，即， 晶界，强烈影响，如果不是决定，许多机械和物理性能的材料，如强度，延展性（材料的能力，弯曲之前，打破），和抗辐射损伤。越来越多的科学数据表明，金属中的晶界可以有许多不同种类的原子排列（也称为多重性），它们之间的过渡会导致显着的性质变化。如果我们有一个更好的理解晶界的多样性和它的结构与性能的关系，科学家和工程师可以设计合成策略，以适应增强纳米结构金属的机械性能的晶界。在这个项目中，加州大学欧文分校的Penghui Cao博士和Huolin Xin博士将使用最前沿的计算建模和电子显微镜工具来研究原子水平上的晶界多重性，并揭示其在确定纳米晶金属如何变形方面的关键作用。 对晶界多样性的基本理解可以促进具有理想机械性能的工程金属的设计，用于结构应用，如航空航天和核能系统。该项目旨在吸引来自不同背景的高中生参与，从而激励并使代表性不足的少数民族能够从事STEM职业。技术概要本项目以揭示晶界的3D原子结构为中心，从根本上理解晶界结构的多样性如何影响纳米结构金属的塑性变形机制。科学上，我们假设纳米晶金属的塑性变形机制可以通过调整晶界的多样性来调整。为了验证这一中心假设，我们提出了研究任务相结合的原子模拟，反应途径模拟，理论建模，电子断层扫描，和原位透射电子显微镜实验。本研究的目的是解决四个主要问题：（1）如何确定晶界的三维原子结构，揭示边界缺陷，结构单元和多重性？(2)晶界缺陷和多重性如何影响晶界的迁移率和迁移机制？(3)是否有可能通过调整晶界状态和结构多样性来控制塑性变形，从而提高纳米晶金属的塑性和延展性？(4)有缺陷的晶界或转变的晶界能产生哪些新的变形机制？从这项研究中获得的物理见解将促进纳米结构金属的结构-性能关系的开发，为通过控制结构，多重性，边界的晶体学分布来有效定制机械行为奠定基础。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估而被认为值得支持。

项目成果

Strong and ductile refractory high-entropy alloys with super formability

• DOI: 10.1016/j.actamat.2022.118602
• 发表时间: 2023-02
• 期刊: Acta Materialia
• 影响因子: 9.4
• 作者: Cheng Zhang;Haoren Wang;Xinyi Wang;Yuanbo T. Tang;Qin Yu;Chaoyi Zhu;Mingjie Xu;Shiteng Zhao;Rui Kou;Xin Wang;B. E. MacDonald;R. Reed;K. Vecchio;P. Cao;T. Rupert;E. Lavernia

Strength softening mitigation in bimodal structured metals

• DOI: 10.1063/5.0075475
• 发表时间: 2022-01
• 期刊: Journal of Applied Physics
• 影响因子: 3.2
• 作者: Han Wang;P. Cao

Direct Observation of Nucleation and Growth Behaviors of Lithium by In Situ Electron Microscopy

• DOI: 10.1021/acsenergylett.3c00180
• 发表时间: 2023-03
• 期刊: ACS Energy Letters
• 影响因子: 22
• 作者: Chunyang Wang;Han Wang;L. Tao;Xinyi Wang;P. Cao;Feng Lin;Huolin L. Xin

Structural heterogeneity governing deformability of metallic glass

• DOI: 10.1016/j.matt.2023.01.016
• 发表时间: 2023-02
• 期刊: Matter
• 影响因子: 18.9
• 作者: Youran Hong;Han Wang;Xing Li;Li Zhong;Han-Ting Chen;Ze Zhang;P. Cao;R. Ritchie;Jiangwei Wang

Fracture universality in amorphous nanowires

• DOI: 10.1016/j.jmps.2023.105210
• 发表时间: 2023-04
• 期刊: Journal of the Mechanics and Physics of Solids
• 影响因子: 5.3
• 作者: K. Zhao;Yunjiang Wang;P. Cao