Nanoscale Sintering Understanding

烧结是一种重要的材料固结致密化策略。它被用来制造形状复杂、接近净形状、设备相对简单的部件。此外，使用烧结可以灵活地定制不同的成分和结构。然而，烧结也是一个复杂的过程。随着纳米颗粒材料的发展，许多传统的烧结理论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材料的加工已经导致了无数的失败和相互矛盾的结果。该奖项支持基础研究，以建立我们对烧结过程的理解，测试从纳米到纳米的烧结方程的可扩展性，并量化气孔在纳米结构演变和收缩中的作用。成功的纳米烧结在改善结构、电学、光学和其他功能特性以及史无前例的纳米结构方面具有令人兴奋的可能性。其应用领域很多，包括能量存储/转换、纳米电子器件、微流控器件、催化剂、微反应器器件和光学元件。该计划还包括广泛的外联活动(如HBCU、当地学校、夏令营)，以增加未被充分代表的群体参与工程，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-纳米结构演化关联的研究，测试纳米级以上烧结方程的可扩展性，并量化气孔在纳米结构演化和收缩中的作用。这项研究有三个关键组成部分。第一种是证明在临界密度以下，由晶颈尺寸推算的收缩依赖于粗化引起的晶粒重构；组织伸缩性只对均匀的微观组织有效。二是证明了在临界密度以上，孔的大小、分布和形状是使晶界扩散和晶界迁移解耦的关键因素，而三维组织重建是提供这种定量数据的独特技术。第三个部分是说明非正常构型的颗粒堆积的烧结取决于堆积结构和扩散机制之间的平衡。这项研究将通过使用可以跟踪单个到多个纳米颗粒的小特征和重建3D纳米结构来提供纳米颗粒排列、微观结构演变和收缩之间亟需的联系。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，还将为网状烧结提供前所未有的管道、新颖的纳米结构和大量的复杂材料设计能力。

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.