EAGER: Engineering Metal-MAX Multilayered Nanocomposites: Hierarchical Microstructures for Tunable Strength and Toughness

对于制造、能源和基础设施中的许多应用，需要具有高强度和高延展性的材料。然而，在同一种材料中发现这两种性质是非常罕见的。许多材料工程方法寻求产生高强度、高延展性材料，包括用交替材料制造纳米结构化层状结构。EARLY概念探索性研究赠款（EAGER）奖支持探索性实验和计算工作，以设计具有可调强度和韧性的多层金属陶瓷纳米复合材料。纳米复合材料将由交替的纳米级金属和陶瓷层组成。陶瓷层是被称为MAX相的陶瓷材料家族的一部分，其本身是层状碳化物或氮化物材料。将金属层与MAX层相结合，形成了一种独特的结构，作为一个复杂的界面网络，最终将控制材料的行为。这些材料在多个技术领域中具有应用，包括高温结构应用、保护涂层、传感器、用于微机电系统（MEMS）的可调阻尼膜，以及在核用途的包覆材料中的潜在应用。具有强而韧性的金属-MAX复合材料的能力，具有改善的机械性能，以满足这些应用的需求，将提供可观的技术和经济效益。该研究将为博士生提供研究生培训，该博士生也将受益于与洛斯阿拉莫斯国家实验室的合作。EAGER研究的目标是：a）设计和合成由交替的金属和MAX相层组成的多层纳米复合材料，其具有减小到纳米级的片层厚度，B）使用纳米机械测试工具建立对分层界面驱动的微观结构和微观结构-性能关系的基本理解（纳米压痕，微压缩），以及c）制定和验证原子模型，该原子模型概述了通过金属的分级设计来控制特定变形模式的激活的前提，MAX纳米层压材料，从而调整其机械性能，以实现更高的强度和韧性。在这项研究成功完成后，可调性能将通过计算过程参数的指导变化来实现，因为我们的纳米级建模将揭示界面的作用和金属-MAX系统的分层微观结构。该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的智力价值和更广泛的影响审查标准进行评估来支持。

For a number of applications in manufacturing, energy and infrastructure, materials with high strength and high ductility are needed. Finding both of these properties in the same material, however, is extremely rare. A number of materials engineering approaches seek to create high strength, high ductility materials, including fabricating nanostructured layered structures with alternating materials. This EArly-concept Grants for Exploratory Research (EAGER) award supports an exploratory experimental and computational effort to engineer multi-layered metal-ceramic nanocomposite materials that exhibit tunable strength and toughness. The nanocomposite will be composed of alternating nanoscale metallic and ceramic layers. The ceramic layers are part of the family of ceramic materials known as MAX phase, which themselves are layered carbide or nitride materials. Combining metal layers with MAX layers results in a unique structure with as a complex network of interfaces which will eventually control the behavior of the material. These materials have applications in multiple technological fields, including high temperature structural applications, protective coatings, sensors, tunable damping films for microelectromechanical systems (MEMS), and potential applications in cladding materials for nuclear use. The ability to have a strong yet ductile metal-MAX composite with improved mechanical behavior to satisfy the demands of such applications will provide considerable technological and economic benefits. The research will provide graduate training for a PhD student who will also benefit from the collaboration with Los Alamos National Laboratory.The objectives of this combined modeling and experimental EAGER research are to: a) design and synthesize multi-layered nanocomposites composed of alternating metallic and MAX phase layers with a lamellar thickness reduced to the nanoscale, b) establish a fundamental understanding of the hierarchical interface driven microstructure and microstructure-property relationships using nano-mechanical testing tools (nanoindentation, micro-compression), and c) formulate and validate atomistic models that outline the premise for controlling the activation of specific deformation mode(s) through hierarchical design of metal-MAX nanolaminates, thus tuning their mechanical properties to achieve greater strength and toughness. Upon successful completion of this research, tunable properties will be realized through guided variations in processing parameters from computation, as our nanoscale modeling will unravel the role of interfaces and the hierarchical microstructure of the metal-MAX system.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.