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：在广泛的工程应用中，许多材料的性能受到限定其整体形状的外表面（固-气界面）、材料内的固-气界面（内部空隙）以及当组成或原子结构/排列突然改变时出现的内部固-固界面（晶界）的影响。在纳米材料中，表面和界面的空间密度高于传统材料，因此它们发挥着更加关键的作用。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各自界面处原子的特定排列。在传统的模型实验中，生成并检查一个表面或晶界。拟议的工作将寻求开发一种新的灵活和有效的实验车辆，用于产生大量的非常特定的几何形状的不同晶界，这些晶界在一个单一的受控化学样品中与高度受控的表面相交。这些样品专门设计用于简化和大大加快各种材料的表面和晶界特性的测量。成功的制造方法的发展将促进表面和晶界性质的知识的快速进步，这些性质在设计具有改进的性能特性的材料中具有基本价值。这项工作将涉及研究生、本科生和高中学生，从而促进受过训练的科学家获得高级学位的发展，并鼓励年轻学生在这一令人兴奋和重要的领域继续深造和研究生水平的培训。技术描述：表面（固-气界面）和晶界材料中的界面（固-固界面）是深刻影响性质和性能的基本微观结构组分。在当前感兴趣的纳米结构材料中，这些界面的空间密度极高，并且它们的重要性被放大。生成、优化和稳定这样的结构将需要表面和界面性质的基础知识。晶界和表面能的测量是必不可少的，但困难和繁琐。在这项工作中，一种新的方法，涉及选择性和局部阻碍单晶籽晶生长到牺牲多晶层将被探索和利用，以产生阵列的双晶岛晶粒的不同取向差在一个单一的样品。这些样品将为陶瓷晶界和表面性质的系统（组合）研究提供理想的载体。在一个单一的样品中的潜在的数百个晶界槽的几何形状的测量，再加上相关的表面取向的分析提供了一种快速的方法，获得的表面能量取向关系，并将这些结果之间的比较和那些来自更繁琐的直接方法。如果成功的话，这种方法将适用于所有类型的材料，促进我们对表面结构（晶体学）-能量关系的知识的快速增长，并鼓励旨在类似地影响晶界性质研究的其他扩展。反过来，这些基本信息可用于设计具有改进性能的材料。