EAGER: Manufacturing Interface Dominated Microstructures in Bulk Metal-Metal Composites for Ultra-High Strength and Formability

纳米结构多层材料——由厚度仅为几纳米的金属层交替组成的材料——是一类具有独特性能的工程材料。批量制造这些多层材料具有重大的工艺挑战。传统上，多层金属多层材料的合成使用的技术可以将总薄膜厚度限制在亚毫米水平，但最近的研究表明，大量的纳米结构金属多层材料可以通过一种称为累积辊键合的替代工艺来制造。这项探索性研究（EAGER）的早期概念资助，支持通过卷接工艺合成镁基纳米多层体所需的基础研究。这些材料作为轻质结构材料有许多用途。由于镁合金比铝合金轻35%，比钢轻78%，因此这项研究的潜在社会影响和回报可能是巨大的。交通运输行业燃油效率的提高意味着更低的工作温度，更持久的组件，减少温室气体排放。在整个消费电子行业的环保项目的推动下，镁满足了对消费电子产品变得更轻、更薄和更具移动性的设计挑战。本次建模与实验结合研究的具体目标是：A)以块体形式制造新的纳米颗粒和富含相界面的金属-金属复合材料（六边形紧密堆积的镁-体心立方铌或钒），b)建立对界面驱动的微观结构发展和微观结构-性能关系的基本理解，以及c)制定和验证一套基于物理的模型，使基本理解和可以预测这些材料的行为。在这项研究成功完成后，将展示加工镁合金纳米层状复合材料的概念能力，并确定将复合材料细化到纳米级以及相关强度和成形性增强的基础科学。

Nanostructured multilayers - materials comprised of alternating layers of metal with thicknesses of just a few nanometers - are a class of engineering materials with unique properties. Fabricating these multilayers in bulk form has significant processing challenges. Traditionally multilayer metallic multilayers have been synthesized using techniques which can limit the total film thickness to sub-millimeter levels, but recent research has demonstrated that bulk quantities of nanostructured metallic multilayers can be manufactured by an alternate process known as accumulative roll bonding. This EArly-concept Grants for Exploratory Research (EAGER) award supports the fundamental research needed for synthesis of magnesium-based nanostructured multilayers in bulk form through the roll bonding process. These materials have many applications as lightweight structural materials. Because magnesium alloys are 35 percent lighter than aluminum alloys and 78 percent lighter than steel, the potential societal impact and pay-offs of this research can be tremendous. Improvements in fuel efficiency for transportation industry means lower operating temperatures, longer-lasting components, and reduced greenhouse gas emissions. Driven by environmental programs across the consumer electronics industry, magnesium meets the design challenges that are instrumental to consumer electronics becoming lighter, thinner, and more mobile. The specific objectives of this combined modeling and experimental research are to: a) fabricate new nano-grained and phase interfaces-rich metal-metal (hexagonal close-packed magnesium - body-centered cubic niobium or vanadium) composites in bulk form, b) establish a fundamental understanding of the interface driven microstructure development and microstructure-property relationships, and c) formulate and validate a set of physics based models that enable fundamental understanding and can predict behavior of such materials. Upon successful completion of this research, proof of concept ability to process magnesium alloy nano-lamellar composite will be demonstrated and the fundamental science behind refining the composite to nano-scale and associated strength and formability enhancements will be determined.