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

在制造业、能源和基础设施领域的许多应用都需要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特性是极其罕见的。许多材料工程方法寻求创造高强度、高延展性的材料，包括用交替材料制造纳米结构层状结构。这一探索性研究（EAGER）早期概念奖支持一项探索性实验和计算工作，以设计出具有可调强度和韧性的多层金属陶瓷纳米复合材料。纳米复合材料将由纳米级金属层和陶瓷层交替组成。陶瓷层是称为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，形成独特的结构，形成复杂的界面网络，最终控制材料的行为。这些材料在多个技术领域都有应用，包括高温结构应用、保护涂层、传感器、微机电系统（MEMS）的可调阻尼膜，以及核用包层材料的潜在应用。能够拥有坚固而延展性的金属- max复合材料，并改善机械性能，以满足此类应用的要求，将提供可观的技术和经济效益。该研究将为一名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。本次建模与实验结合的EAGER研究的目的是：a)设计和合成由交替金属相层和MAX相层组成的多层纳米复合材料，层层厚度降至纳米级；b)利用纳米力学测试工具（纳米压痕、微压缩）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；c)建立并验证原子模型，该模型概述了通过金属- max纳米层合材料的分层设计来控制特定变形模式激活的前提，从而调整其力学性能以获得更高的强度和韧性。在这项研究的成功完成后，我们的纳米尺度建模将揭示界面的作用和金属- max系统的分层微观结构，从而通过从计算中引导加工参数的变化来实现可调性能。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

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.