Principles for Formation of Transversely Modulated Heterophase Nanostructures

横向调制异相纳米结构的形成原理

• 批准号: 0907122
• 负责人: Hugh Bruck
• 金额: $ 36万
• 依托单位: University of Maryland, College Park
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-07-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0907122&HistoricalAwards=false
• 关键词: Principles; Formation; Transversely; Modulated; Heterophase

TECHNICAL SUMMARYIn this research project, a new class of materials with controlled transversely modulated heterophase nanostructures (TMNS) will be developed. The research will integrate theory, modeling, experimental characterization, and design of TMNS with controlled scale and morphology. The basic idea of this research effort is to design TMNS by exploiting epitaxial self-assembling of constituent phases on a crystalline substrate. Formation of such self-assembled nanostructures requires establishing epitaxial relations between each phase and the substrate. These epitaxial relations lead to self-organization of constituent phases and formation of 3D heteroepitaxial nanostructures with coherent or semi-coherent interfaces. By selecting different substrates or substrate orientations and changing the thickness of the nanostructured layer, it is possible to control morphology of the self-assembled nanostructures on a scale that is difficult to obtain with other techniques. Because of the nanoscale of the component phases, dislocation-mediated mechanisms are suppressed resulting in significant elastic strain. Therefore, controlling this stress becomes a new mechanism for manipulating film properties, similar to semiconductor heterostructures. The goal of this research is to develop experimentally verified theoretical principles and computational tools to design materials with modulated nanostructures using epitaxial control. The ability to control morphology, scale, and stress state will be demonstrated. Self-assembled modulated structures on substrates will be formed as a result of either: (a) solid-solid phase transformation (polymorphic, martensitic, or eutectoid), or (b) eutectic crystallization from an amorphous or liquid phase. As a consequence of this research, new principles of design will be developed for thin film materials consisting of controlled heterophase nanostructures for tailoring of interfaces at the nanoscale, as well as the associated processing, characterization, and modeling techniques necessary to realize TMNS.NON-TECHNICAL SUMMARYNanostructured materials are important for a wide spectrum of structural and functional applications, such as sensors, actuators, magnetic recording media, wear resistant coatings, high temperature or corrosion resistant structural materials, and thermoelectric devices. This research will provide an entirely new principle for designing materials with controlled heterophase nanostructures that will lead to materials that are stronger, better at sensing, and more durable, as well as new materials that would not otherwise be possible such as multilayered composite structures whose properties can be actively tuned through self-assembly of the nanostructures. Broader impacts of this research include a coupled theoretical and experimental approach to research and education that ensures broad access to the knowledge needed to enhance the interest and skills of future engineers and researchers using sputtering techniques, nanoindentation, and computational materials science.

技术概述在本研究项目中，将开发一类具有受控横向调制异相纳米结构（TMNS）的新材料。本研究将整合理论、模型、实验特性以及具有可控制规模与形态的TMNS设计。本研究工作的基本思想是设计TMNS利用外延自组装的结晶衬底上的组成相。这种自组装纳米结构的形成需要在每个相和衬底之间建立外延关系。这些外延关系导致自组织的组成相和形成的三维异质外延纳米结构的连贯或半连贯的接口。通过选择不同的基底或基底取向并改变纳米结构化层的厚度，可以在用其他技术难以获得的尺度上控制自组装纳米结构的形态。由于组分相的纳米级，位错介导的机制被抑制，导致显著的弹性应变。因此，类似于半导体异质结构，控制这种应力成为操纵膜特性的新机制。本研究的目标是开发实验验证的理论原理和计算工具，设计材料与调制纳米结构使用外延控制。将证明控制形态、规模和应力状态的能力。衬底上的自组装调制结构将由于以下原因而形成：（a）固-固相变（多晶型、马氏体或共析），或（B）从非晶或液相共晶结晶。作为这项研究的结果，新的设计原则将被开发用于薄膜材料，该薄膜材料由用于在纳米尺度上定制界面的受控异相纳米结构组成，以及实现TMNS所需的相关处理、表征和建模技术。非技术概述纳米结构材料对于广泛的结构和功能应用是重要的，例如传感器、致动器、磁记录介质、耐磨涂层、耐高温或耐腐蚀结构材料和热电装置。这项研究将为设计具有受控异相纳米结构的材料提供一种全新的原理，这将导致材料更坚固，更好地传感，更耐用，以及其他不可能的新材料，例如多层复合结构，其特性可以通过纳米结构的自组装进行主动调整。这项研究的更广泛的影响包括研究和教育的理论和实验方法，确保广泛获得所需的知识，以提高未来工程师和研究人员使用溅射技术，纳米压痕和计算材料科学的兴趣和技能。