A Combinatorial Approach to Grain Boundary Studies: Bicrystal Arrays via Lithographically Modulated Seed Growth

晶界研究的组合方法：通过光刻调节晶种生长的双晶阵列

• 批准号: 0606121
• 负责人: Andreas Glaeser
• 金额: $ 40.5万
• 依托单位: University of California-Berkeley
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0606121&HistoricalAwards=false
• 关键词: Combinatorial; Approach; Grain; Boundary; Studies

NON-TECHNICAL DESCRIPTION: The performance of many materials in a wide range of engineering applications is influenced by the external surfaces (solid-vapor interfaces) that define their overall shape, solid-vapor interfaces within the material (internal voids), and by internal solid-solid interfaces (grain boundaries) that arise when the composition or the atomic structure/arrangement changes abruptly. In nanoscale materials, the spatial density of surfaces and interfaces is higher than in conventional materials, and therefore they play an even more critical role. Important characteristics of surfaces and grain boundaries are their energy and how these energies depend upon the specific arrangement of atoms at the respective interfaces. In conventional model experiments, one surface or grain boundary is generated and examined. The proposed work will seek to develop a new flexible and efficient experimental vehicle for generating large numbers of distinct grain boundaries of very specific geometry that intersect highly-controlled surfaces in a single sample of controlled chemistry. The samples are specifically designed to simplify and greatly accelerate measurements of surface and grain boundary properties in a wide range of materials. The development of a successful fabrication approach would promote rapid advances in the knowledge of surface and grain boundary properties that have fundamental value in designing materials with improved performance characteristics. This work will involve students at the graduate, undergraduate, and high-school levels, and thereby promote the development of trained scientists with advanced degrees, and encourage younger students to pursue further study and graduate-level training in this exciting and vital area.TECHNICAL DESCRIPTION: Surfaces (solid-vapor interfaces) and grain boundaries (solid-solid interfaces) in materials are essential microstructural components that profoundly impact properties and performance. In the nanostructured materials of current interest, the spatial density of these interfaces is extremely high, and their importance is amplified. Generating, optimizing and stabilizing such structures will require fundamental knowledge of the surface and interface properties. Measurements of grain boundary and surface energetics are essential, but difficult and tedious. In this work, a novel approach involving selectively and locally impeded single crystal seed growth into a sacrificial polycrystalline layer will be explored and exploited to generate arrays of bicrystal island grains of varying misorientation in a single sample. The samples will provide an ideal vehicle for systematic (combinatorial) studies of grain boundary and surface properties in ceramics. Measurements of the geometry of potentially hundreds of grain-boundary-grooves in a single sample, coupled with analysis of the relevant surface orientations provides a rapid method of obtaining the surface energy-orientation relationship, and comparisons will be made between such results and those derived from more tedious direct methods. If successful, such an approach would have applicability to the full range of material types, promote rapid gains in our knowledge of surface structure (crystallography)-energy relationships, and encourage additional extensions designed to similarly impact studies of grain boundary properties. In turn, this fundamental information can be used to design materials with improved performance.

非技术描述：许多材料在广泛的工程应用中的性能受到外表面（固体蒸气接口）的影响，这些表面定义了它们的整体形状，材料内的固体蒸气接口（内部空间），以及内部当组成或原子结构/布置突然变化时，出现的固相界面（晶界）。在纳米级材料中，表面和界面的空间密度高于常规材料，因此它们起着更为关键的作用。表面和晶界的重要特征是它们的能量以及这些能量如何取决于原子在相应界面上的特定排列。在常规模型实验中，生成一个表面或晶界。拟议的工作将旨在开发一种新的灵活，有效的实验工具，以产生大量非常特定的几何形状的不同晶界，这些几何形状与单个受控化学样本中的高度控制的表面相交。这些样品是专门设计的，以简化并大大加速了在各种材料中的表面和晶界性质的测量。成功制造方法的发展将促进在设计具有改善性能特征的材料方面具有基本价值的表面和晶界特性知识的快速进步。这项工作将涉及毕业生，本科和高中级别的学生，从而促进具有高级学位的训练有素的科学家的发展，并鼓励年轻的学生在这个令人兴奋和重要的领域进行进一步的学习和研究生培训。描述：材料中的表面（固相接口）和晶界（固体界面）是必不可少的微观结构组件，对性质和性能产生了深远的影响。在当前感兴趣的纳米结构材料中，这些接口的空间密度非常高，并且它们的重要性被放大。产生，优化和稳定这种结构将需要对表面和界面特性的基本知识。晶界和表面能量的测量是必不可少的，但困难和乏味。在这项工作中，将探索和利用一种新的方法，该方法涉及选择性和局部阻碍的单晶种子生长到牺牲多晶层中，以生成单个样本中不同不良方向的双晶岛晶粒阵列。样品将为陶瓷中晶界和表面特性的系统（组合）研究提供理想的载体。单个样品中潜在数百个晶粒式山之间的几何形状的测量，再加上相关表面取向的分析提供了一种快速获得表面能量取向关系的方法，并将进行此类结果和派生的结果进行比较来自更乏味的直接方法。如果成功的话，这种方法将适用于各种材料类型，促进我们对表面结构（晶体学） - 能源关系的知识的快速增长，并鼓励旨在类似地影响晶界特性研究的其他扩展。反过来，此基本信息可用于设计具有改进性能的材料。