EAGER: Bulk Nanostructured Metals from Twinned Nanowires

非技术摘要：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。一块连续的金属是由紧密堆积的非常细小的颗粒组成的。这些颗粒的大小和结构，以及它们堆积在一起的方式，决定了大块材料的宏观性质。通常，这些颗粒是在整个散装材料的生长过程中形成的，在进一步的加工过程中可以在某种程度上进行重组。这个项目探索了一种对比的方法，在这种方法中，离散的金属纳米晶体首先被化学合成以产生明确的结构，然后组装和致密以产生最终的块体纳米结构金属。这种新方法允许更高的自由度来控制金属颗粒的大小、结构和取向，并可能创造出具有新特性的金属材料。技术摘要：制备块体纳米结构金属的新方法从根本上不同于现有的方法，这些方法基于粗晶金属的广泛塑性变形，通过电镀或溅射技术逐个原子地生长，以及微米级金属粉末的固结。在新的策略中，定义明确的金属颗粒(即纳米线)首先是“逐个原子？”合成的。然后组装成最终的块状金属“逐粒”。这可以有效地将颗粒微结构和颗粒取向的调节解耦，导致新的块体纳米结构金属具有以前无法获得的微结构(例如，颗粒形状、取向和纳米孪晶)和新的性能。该项目解决了块体纳米结构合金(面向冶金)和胶体纳米材料(面向材料化学)之间长期缺失的联系。如果成功，它将激励和催化这两个独立的纳米材料研究领域之间早就应该进行的合作。接受该项目培训的学生代表了一种新型的材料科学家，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.