Advanced Nanocrystalline Ceramic Matrix Composites with Improved Fracture Toughness: Processing, Characterization & Modeling

该项目的目标是对氧化铝基纳米复合材料的加工、表征和建模进行广泛的研究，以充分了解加工、结构和力学性能之间的相互作用。一般而言，陶瓷纳米复合材料的常规增韧和特殊增韧机制与不同长度尺度上发生的过程有关，因此需要从材料的多尺度力学角度进行理论描述。后者是分析多尺度建模的主要目标，是拟议研究项目的一部分。低密度、化学惰性和高强度/硬度使陶瓷成为一种非常有前途的结构应用候选材料。然而，陶瓷的断裂韧性相对较低，阻碍了陶瓷在此类应用中的应用。因此，研究的重点是通过加入第二相来提高氧化铝的断裂韧性，以制备适合于结构应用的陶瓷基复合材料[CMCs]。智力的优点在于使用从PI收集的微观结构和机械性能数据？研究以及其他对纳米晶陶瓷基复合材料中的增韧机理进行解析建模的研究？一种以界面增韧机制为主的尺寸体系。拟议的研究活动的更广泛的影响是开发CMC的准确模型，这将有助于整个科学界有朝一日预测CMC的理论机械性能和主要增韧机制。这些模式可用于教育所有级别的学生，并将促进工程科学中代表性不足的人的教学。

The goal of the proposed project is to conduct an extensive investigation into processing, characterization and modeling of alumina-based nanocomposites in order to fully understand the interplay between processing, structure, and mechanical properties. In general, the conventional and special toughening mechanisms in ceramic nanocomposites are associated with processes occurring on various length scales and thereby need to be theoretically described in terms of multiscale mechanics of materials. The latter is the main aim of analytical multiscale modeling, a part of the proposed research project. The low density, chemical inertness, and high strength/hardness make ceramics a very promising candidate for structural applications. However, utilization of ceramics for such applications is impeded by their relatively low fracture toughness. Thus, the focus of the proposed research is to improve the fracture toughness of alumina by incorporation of second phases to create ceramic matrix composites [CMCs] suitable for structural applications. The intellectual merit lies in the use of microstructural and mechanical properties data collected from PIs? research as well as others to analytically model the toughening mechanisms within nanocrystalline ceramic matrix composites ? a size regime in which interfacial toughening mechanisms are dominant.The broader impacts of the proposed research activity is to develop accurate modeling ofCMCs which would help the scientific community at large to someday predict the theoretical mechanical properties and dominant toughening mechanisms of CMCs. These models can be used to educate students of all levels and will facilitate teaching of underrepresented people in engineering sciences.