Nanoscale Sintering Understanding

烧结是一种重要的材料固结和致密化策略。它用于制造形状复杂、接近净形、设备相对简单的零件。此外，不同的成分和结构可以灵活地使用烧结定制。然而，烧结也是一个复杂的过程。随着纳米基材料的发展，许多传统的烧结理论已经无法预测新的烧结行为；依靠现有的烧结知识来指导纳米颗粒基材料的加工已经导致了许多失败和矛盾的结果。该奖项支持基础研究，以建立我们对烧结过程的理解，测试纳米级以上烧结方程的可扩展性，并量化纳米结构演变和收缩中孔隙的功能。成功的纳米烧结在结构、电学、光学和其他功能特性的改进和前所未有的纳米结构方面代表了令人兴奋的可能性。应用领域众多，包括能量存储/转换、纳米光子器件、微流体器件、催化剂、微反应器器件和光学元件。该计划还包括广泛的外展活动（如HBCU，当地学校，营地），以增加工程领域代表性不足的群体的参与，特别是在纳米材料领域。该奖项支持建立直接和定量的烧结收缩-纳米结构演变相关性的研究，测试纳米级及以上烧结方程的可扩展性，并量化孔隙在纳米结构演变和收缩中的作用。这项研究有三个关键组成部分。首先是证明在临界密度以下，由晶粒颈尺寸推断的收缩取决于粗化引起的晶粒重构；微观结构的可扩展性只适用于均匀的微观结构。二是表明临界密度、孔径、分布和形状是将晶界扩散与晶界迁移解耦的关键因素，而三维微观结构重建是提供此类定量数据的独特技术。第三个组成部分是说明颗粒填料在不寻常配置的烧结是依赖于填料结构和扩散机制之间的平衡。这项研究将提供纳米颗粒排列、微观结构演变和收缩之间急需的联系，通过使用可以跟踪单个到多个纳米颗粒和重建三维纳米结构的小特征。所获得的烧结知识不仅将为基于纳米颗粒的烧结提供有效的解决方案，而且还将为净形状烧结、新型纳米结构和大量复杂材料设计能力提供前所未有的管道。

Sintering is an important materials consolidation and densification strategy. It is used to make components with complex shapes, in near net-shapes, and with relatively simple equipment. Also, different compositions and structures can be flexibly tailored using sintering. However, sintering is also a complex process. With the progress of nanoparticle-based materials, many conventional sintering theories cannot predict new sintering behaviors; relying on existing sintering knowledge to guide nanoparticle-based material processing has led to numerous failures and contradictory results. This award supports fundamental research to build our understanding of the sintering process, to test the scalability of sintering equations from nanometers up, and to quantify the function of pores in nanostructure evolution and shrinkage. Successful nano-sintering represents exciting possibilities in improved structural, electrical, optical, and other functional properties and unprecedented nanostructures. The application areas are numerous, including energy storage/conversion, nanophotonic devices, microfluidic devices, catalysts, microreactor devices, and optical components. This program also includes extensive outreach activities (such as HBCU, local schools, camps) to increase the participation of underrepresented groups in engineering, especially in the area of nanomaterials. This award supports research to build direct and quantitative sintering shrinkage-nanostructure evolution correlations, test the scalability of sintering equations from nanoscale and up, and quantify the function of pores in nanostructure evolution and shrinkage. There are three key components to this research. The first is to demonstrate that below a critical density, shrinkage extrapolation from grain neck size is dependent on coarsening-induced grain-reconfiguration; microstructure scalability is only valid for homogenous microstructures. The second is to show that above the critical density, pore size, distribution, and shape are critical factors for decoupling grain boundary diffusion from grain boundary migration and 3D microstructure reconstruction is a unique technique to provide such quantitative data. The third component is to illustrate that sintering of particle packing in unusual configurations is dependent on the balance between packing structures and diffusion mechanisms. The research will provide the much needed linkage between nanoparticle arrangement, microstructural evolution, and shrinkage by using small features that can track individual to multiple nanoparticles and reconstructing 3D nanostructures. The sintering knowledge gained will provide not only effective solutions to nanoparticle-based sintering but also never-before conduits for net-shape sintering, novel nanostructures, and a vast array of complex material design capabilities.