RII Track-4: Mechanistic Design of Hierarchical Metal-MAX Multilayered Nanocomposites

RII Track-4：分层 Metal-MAX 多层纳米复合材料的机理设计

• 批准号: 1929208
• 负责人: Siddhartha Pathak
• 金额: $ 30万
• 依托单位: Board of Regents, NSHE, obo University of Nevada, Reno
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2020
• 资助国家: 美国
• 起止时间: 2020-06-01 至 2020-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1929208&HistoricalAwards=false
• 关键词: RII; Track; Mechanistic; Design; Hierarchical

Nanocomposites are a class of composite materials where the size of the base or constituent materials are on the nanometer length scale - one nanometer being one-billionth of a meter. They can offer unprecedented properties beyond those currently studied and used. The goal of this fellowship proposal is to augment the advantages of a multilayered design in a metal-ceramic nanocomposite that is hypothesized to exhibit tunable strength and toughness, by the selective activation of deformation mechanisms at the nanoscale. The metal-ceramic multilayered nanocomposite is composed of alternating metallic and MAX phase layers with a lamellar thickness reduced to the nanoscale. Because of the ideal, highly oriented structure that prevails across the film, each film contains thousands of "like layers", and a high density of interfaces. MAX phases are a family of ceramic materials consisting of laminated ternary carbide or nitride materials, and they represent a novel class of layered solids, where Mn+1Xn layers are interleaved with pure A-group element layers. These metal-MAX multilayered nanocomposite thin films show uniform interface spacing (~2 to 100’s of nm apart) and uniform interface plane and crystallography throughout the film. MAX phases have applications in multiple technological fields, including high temperature structural applications, protective coatings, sensors, tunable damping films for microelectromechanical systems, etc., along with 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. This research is an integrated collaboration planned between the principal investigator (PI) and the Center for Integrated Nanotechnologies, Sandia National Laboratories (CINT-SNL), which will support a postdoctoral researcher, and enable extended collaborative visits and infrastructure development opportunities at the nation’s premier national laboratory at CINT-SNL. Undergraduate education in the capstone senior design projects in the Materials department at the PI’s university will particularly benefit from this collaboration by having mentors (and possible visitations to CINT-SNL) from both national laboratory and university. The objectives of this fellowship project are to leverage a fundamental understanding of the activation and confinement of deformation mechanisms directly linked to the hierarchical structure at the nanoscale in multilayered nanocomposite materials, to potentially enable tunable strength and toughness. Unlike other various multilayered systems that have been pursued in the past, the metal-MAX nanocomposites studied here are composed of a unique hierarchical topology - as interfaces between the layers are in direct competition with the internal interfaces within the MAX layers to drive the tunable macroscopic mechanical behavior. Guided by experimental synthesis and novel nanomechanical testing capabilities of the PI, computational modeling at CINT-SNL will complement the experimental component to study the fundamental mechanisms (e.g., dislocations and ripplocations) within the metal-MAX hierarchical structure. Outcomes from the fellowship project will include the development of correlations between the metal-MAX hierarchical structure, its fundamental deformation mechanisms and the resulting mechanical properties, namely strength and toughness.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.

纳米复合材料是一类复合材料，基本或构成材料的大小在纳米长度尺度上 - 一个纳米分别为米三分之一。他们还可以提供前所未有的属性，而不是当前研究和使用的属性。该奖学金提案的目的是通过选择性激活纳米级变形机制的选择性激活，可以在金属陶瓷纳米复合材料中增强多层设计的优势。金属陶瓷多层纳米复合材料由替代金属和最大相层组成，其层状厚度还原为纳米级。由于整个电影中盛行的理想，高度定向的结构，每个电影都包含数千个“像层”和高密度的接口。最大相是由层状三元碳化物或氮化物材料组成的一系列陶瓷材料家族，它们代表了一类新型的分层固体，其中Mn+1xn层与纯A-Group元素层交织在一起。这些金属最大的多层纳米复合薄膜显示均匀的界面间距（相距〜2至100），整个膜中均匀的界面平面和晶体学。最大阶段在多个技术领域都有应用，包括高温结构应用，保护性涂料，传感器，可调式阻尼膜，用于微电机械系统等，以及用于核用核材料的潜在应用。具有强大而延性的金属 - 最大综合材料具有改进的机械行为以满足此类应用的需求的能力将提供考虑的技术和经济利益。这项研究是一项计划的综合协作（PI）和综合纳米技术中心，Sandia国家实验室（CINT-SNL），该中心将支持博士后研究人员，并在该国Cint-Snl的Cint-Snl国家领先国家实验室中启用扩展的协作访问和基础设施开发机会。 PI大学材料系的Capstone高级设计项目的本科教育将特别受益于国家实验室和大学的导师（以及对Cint-SNL的可能访问）。该奖学金项目的目标是利用对与多层纳米复合材料中纳米级直接相关的变形机制的激活和限制的基本理解，以实现可调的强度和韧性。与过去追求的其他各种多层系统不同，这里的金属量纳米复合材料由唯一的层次拓扑组成 - 因为层之间的接口与最大层中的内部接口直接竞争，以驱动可调的可调型机械机械行为。在PI的实验合成和新颖的纳米力学测试能力的指导下，CINT-SNL的计算建模将完成实验成分，以研究金属 - 最大层次结构内的基本机制（例如，脱位和裂开）。奖学金项目的结果将包括金属 - 最大层次结构，其基本变形机制和由此产生的机械性能之间的相关性，即强度和韧性。该奖项反映了NSF的法定任务，并通过评估该基金会的智力优点和广泛的影响来评估NSF的法定任务，并被认为是珍贵的支持。