FABRICATIONS AND MECHANICAL PROPERTIES OF SUPER STRONG FUNCTIONAL NANOSTRUCTURES

纳米电子学的功能、寿命和商业上的成功最终取决于我们成功设计和设计组成它们的小尺度结构的机械性能的能力。为此，必须对纳米电子学的物理特性和可靠性有一个基本的了解，并将其作为亚微米到纳米尺度的函数。然而，在整体上效果良好的强化技术往往难以在纳米级上实现。例如，大块纳米晶Ni试样具有优异的机械强度，但由于晶界滑动，当样品缩小到小于100 nm时，它们会软化。相反，随着样品尺寸的减小，退火良好的单晶结构表现出优异的机械强度。最近提出的一些解释这种强度尺寸效应的机制包括位错饥饿效应、随机行为和纳米孪晶的形成。这些机制理论是纳米结构所特有的；然而，它们仍处于起步阶段，需要进一步发展。本研究有三个目的：1)探索合金化和析出对金属纳米结构力学性能的影响；2)研究碳纳米管-金属基纳米复合材料的力学变形行为；3)制定制造超强纳米结构的指导方针。拟议的项目将在我们的研究设施中进行，使用安装在场发射扫描电子显微镜内的最先进的原位纳米压头。这被认为是加拿大第一个也是唯一的原位纳米级机械测试仪器，也是世界上为数不多的仪器之一。我们期望该提案项目将导致对溶质/沉淀效应和碳纳米管对纳米结构强度的影响的深入了解，从而使开发坚固且能够实现功能行为的结构成为可能。

The functionality, lifetime, and commercial success of nanoelectronics ultimately depend on our ability to successfully design and engineer the mechanical properties of the small scale structures that comprise them. To that end, it is imperative to gain a fundamental understanding of the physical properties and reliability of nanoelectronics as a function of size in the sub-micron to nanometer scales. However, strengthening techniques that work well in bulk are often difficult to implement at the nanoscale level. For example, bulk nanocrystalline Ni specimens exhibit superior mechanical strength, but because of the grain boundary sliding, they soften when the sample is reduced to smaller than 100 nm. Conversely, well annealed single crystalline structures, which are soft in bulk, exhibit superior mechanical strength as the sample dimension decreases. Some proposed mechanisms recently suggested to explain this strength size effect include the dislocation starvation effect, stochastic behaviors, and nano-twin formations. These mechanism theories are unique to nanostructures; however, they are still in their infancy and need further development. This study has three objectives: 1) explore the alloying and precipitation effects on the mechanical properties of metallic nanostructures; 2) investigate the carbon nanotube-metal matrix nanocomposite mechanical deformation behaviors; and 3) develop guidelines to fabricate super-strong nanostructures. The proposed project will be conducted in our research facility using a state-of-the-art in-situ nanoindenter installed within a field-emission scanning electron microscope. This is believed to be the first and only in-situ nanoscale mechanical testing instrument in Canada, and one of only a few in the world. We anticipate that the proposal project will lead to an in-depth understanding of the solute/precipitation effect and the CNT influences on the strength of nanostructures, making it possible to develop structures that are strong and able to fulfill the functional behaviors.