EAGER: Bulk Nanostructured Metals from Twinned Nanowires

金属在电子和基础设施中有着广泛的用途，是现代文明的物质基础。一个连续的金属片是由密集的，非常细的颗粒。这些颗粒的尺寸和结构以及它们堆积在一起的方式决定了块体材料的宏观性质。通常，这些晶粒在整个块体材料的生长期间形成，并且可以在进一步处理期间稍微重构。该项目探索了一种对比方法，首先化学合成离散的金属纳米晶体以产生明确的结构，然后组装和致密化以产生最终的大块纳米结构金属。这种新方法允许更高的自由度来控制金属晶粒的尺寸，结构和取向，并可能创造具有新特性的金属材料。技术摘要：用于创建散装纳米结构金属的新方法从根本上离开当前的，这是基于广泛的塑性变形的粗晶粒金属，原子通过电镀或电镀为基础的技术，原子的增长，并巩固微米尺寸的金属粉末。在新策略中，定义明确的金属颗粒（即，纳米线）首先是“一个原子接一个原子地”合成的。然后一粒一粒地组装以构成最终的大块金属。这可以有效地使晶粒微结构和晶粒取向的调整解耦，从而产生具有先前无法获得的微结构（例如，晶粒形状、取向和纳米孪晶）和新颖的性质。该项目致力于解决大块纳米结构合金（以纳米材料为导向）和胶体纳米材料（以材料化学为导向）之间长期缺失的联系。如果成功，它将激发和催化这两个独立的纳米材料研究领域之间的合作。在该项目中接受培训的学生代表了一种新的材料科学家，他们可以将冶金学与胶体纳米材料联系起来，为这两个领域带来新的思维方式。

Non-technical Abstract:Metals have widespread uses in electronics and infrastructure, and are the material foundation of modern civilization. A continuous piece of metal is made of densely packed, very fine grains. The size and structure of these grains, and the way they pack together determine the macroscopic properties of the bulk material. Typically, these grains are formed during the growth of the entire bulk material, and can be somewhat restructured during further processing. This project explores a contrasting approach, in which discrete metal nanocrystals are first chemically synthesized to yield well-defined structure, then assembled and densified to yield the final bulk nanostructured metal. This new approach allows for much higher degree of freedom to control the size, structure, and orientation of the metal grains, and can potentially create metal materials with novel properties. Technical Abstract:The new approach for creating bulk nanostructured metals departs fundamentally from the current ones, which are based on extensive plastic deformation of coarse-grained metal, atom-by-atom growth through electroplating or sputtering-based techniques, and consolidation of micron-size metal powders. In the new strategy, well-defined metal grains (i.e., nanowires) are first synthesized "atom-by-atom?" and then assembled to construct the final bulk metal "grain-by-grain". This can effectively decouple the tuning of grain microstructures and grain orientations, leading to new bulk nanostructured metals with previously unattainable microstructures (e.g., grain shape, orientation and nano-twinning) and novel properties. The project addresses a long missing connection between bulk nanostructured alloys (metallurgy-oriented) and colloidal nanomaterials (materials chemistry-oriented). If successful, it will inspire and catalyze a long overdue collaboration between these two independent areas of nanomaterials research. Students trained in the project represent a new breed of material scientists that can connect metallurgy with colloidal nanomaterials, bringing fresh mindsets to both areas.