Collaborative Research: Strengthening Metallic Nanofoams Through Ligament Scale Materials Design

纳米尺度的金属泡沫表现出几个显着的性能。目前最常见的纳米结构泡沫是由纯金属制成的，它们在催化、电池和光学等领域表现出卓越的性能。然而，这些金属泡沫通常是易碎的并且难以整合到工程应用中。迄今为止，机械强化泡沫以产生坚固材料的能力在纯金属中受到限制。该奖项支持旨在创造一种新材料的研究-复合纳米泡沫-显示与纯金属泡沫相同的显着性能，但具有显着增强的结构完整性。通过这项工作设计的新材料将使研究人员和工程师能够利用独特的性能，而不会在机械处理或服务过程中出现故障。从这项研究中获得的基础知识可以用于设计和制造低成本和高强度的催化剂，具有更高容量和更快充电时间的燃料电池，具有高抗疲劳性的生物医学植入物，以及更轻和更强的储氢单元。克拉克森和普渡两所大学的一个研究小组将开展这项工作，让两所学校的学生接触到推进研究所需的日益普遍的远程合作。该研究小组将在原子和介观尺度（分子动力学和有限元分析）的材料工程的计算方法耦合到制造和表征复合纳米结构泡沫的实验方法。工作假设是，用纳米结构多层涂覆单个泡沫韧带将导致形成更强的泡沫。为了制造这些材料，铜和镍将被电镀，以在电纺聚合物的纸状垫的模板上形成核壳层，这些核壳层将被氧化，然后被还原，以形成纳米级的铜金属线。脉冲激光热弹性激发将用于确定分散和振动共振，以获得泡沫的体弹性性能。这些结果将直接与复合材料的有限元模拟进行比较，以隔离几何形状和韧带性能的影响。泡沫强度将预测分子动力学模拟的基础上的韧带，这将提供信息，以饲料到有限元模型，并最终比较的屈服强度的实验研究，使用纳米压痕与平冲几何形状。这项工作的智力意义将是由计算材料工程指导的一类新材料的开发，以及制造和测试纳米级金属泡沫的新技术的开发。

Nanoscale metal foams exhibit several remarkable properties. The most common nanostructured foams are currently made of pure metals, and they demonstrate exceptional performance in areas such as catalysis, batteries, and optics. These metal foams are, however, often fragile and difficult to integrate into engineering applications. The ability to mechanically strengthen foams to create robust materials has heretofore been limited in pure metals. This award supports research aimed at creating a new class of materials - composite nano foams - which display the same remarkable properties as pure metal foams, but with significantly enhanced structural integrity. The new materials designed through this work will allow researchers and engineers to exploit unique properties without suffering failure during mechanical handling or service. The fundamental knowledge gained from this research may be used in designing and manufacturing catalysts with low cost and high strength, fuel cells with higher capacity and faster charging times, biomedical implants with high fatigue resistance, and lighter and stronger hydrogen storage units. A team of researchers at two universities, Clarkson and Purdue, will carry out this work, exposing students at both schools to the increasingly common long-distance collaborations needed for advancing research. The research team will couple computational methods of materials engineering at the atomistic and mesoscopic scales (molecular dynamics and finite element analysis) to experimental methods of manufacturing and characterizing composite nanostructured foams. The working hypothesis is that coating individual foam ligaments with nanostructure multilayers will result in the formation of stronger foams. To create these materials, copper and nickel will be electroplated to form core-shell layers on templates of paper-like mats of eletrospun polymers, which will be oxidized and then subsequently reduced to form nanoscale copper metal wires. Pulsed-laser thermoelastic excitation will be used to determine the dispersion and vibrational resonance to obtain the foam's bulk elastic properties. These results will be compared directly to finite element simulations of the composite to isolate the effects of geometry and ligament properties. Foam strength will be predicted based on molecular dynamics simulations of the ligaments, which will provide information to feed into the finite element models, and finally compared to experimental studies of the yield strength using nanoindentation with a flat punch geometry. The intellectual significance of this work will be the development of a new class of materials guided by computational materials engineering, and the development of novel techniques for manufacturing and testing nanoscale metallic foams.