Low-cost Manufacturing of Bioinspired Damage-Tolerant Ceramic Composites

尽管陶瓷-金属复合材料具有良好的性能，但迄今为止，它们尚未在商业上应用，这在很大程度上是由于加工成本和挑战。用于制造层状陶瓷-金属复合材料的常规方法是将金属相熔融渗透到陶瓷支架的间隙中。差距越小，渗透越困难。由于大多数金属和陶瓷之间的润湿性差，该工艺需要高压和高温将熔融金属挤压到陶瓷相中的间隙中。该项目旨在开发受自然启发的制造策略，以实现陶瓷-金属复合材料的低成本制造。天然材料，如骨头和贝壳的贝壳部分，已经发展出结构复合材料，使用一组相当普通的成分，表现出非凡的机械性能。例如，贝壳将脆性陶瓷材料转化为超韧材料（珍珠层），通过加入约5%的聚合物，在分层？实体店微观结构科学界在确定生物结构复合材料的设计原则方面非常成功。然而，制造业知识差距依然存在。这些挑战包括陶瓷砖之间的小间隙渗透的挑战，获得韧性（同时坚固）砂浆的挑战;设计适当（金属-陶瓷）界面的挑战;以及高成本。低成本金属制造工艺&陶瓷复合材料可显著增加其在包括汽车、航空航天、石油和国防在内的各种工业中的应用，在诸如高性能耐磨部件、切削工具、轻质结构复合材料和航空发动机部件的产品中的应用。由于这些原因，该项目直接影响美国的经济福利和国家安全。该项目的教育目标是增加纳米技术的多样性-干通过？纳米探测器？高中生暑期课程，特别重视女学生，包括拉丁美洲人。本研究的目的是探讨陶瓷复合材料损伤容限结构应用的加工和制造的机制。该项目的重点是了解纳米孪晶金属渗透到纳米间隙（100纳米）的三维多孔陶瓷支架脉冲电沉积。保守估计表明，该工艺的能耗比传统的熔融金属浸渗工艺小200倍以上。电沉积中的液体电解质与熔融金属相比具有小得多的粘度，因此可以有效地渗透到陶瓷砖之间的小间隙中。一类金属，击败了强度和韧性之间的权衡是什么？纳米孪晶金属.纳米孪晶金属具有高密度的共格孪晶界，这已被证明可以提高强度和延展性。脉冲电沉积是制备纳米孪晶金属的主要方法之一。为了解决金属-陶瓷界面的挑战，计划在陶瓷砖上无电沉积薄金属层，这将导致均匀的涂层，以及陶瓷和金属之间的强粘附力。本研究如果成功，将在以下几个方面产生新的基础知识：（i）脉冲电沉积直接合成纳米孪晶金属层压陶瓷支架的生长机理和微观结构：（ii）纳米通道（100 nm）中脉冲电沉积过程的动力学;（三）纳米渗透该奖项反映了NSF的法定使命，并通过使用基金会的学术价值和更广泛的影响审查标准。

Despite favorable properties of ceramic-metal composites, they have not been applied commercially to date, due in large part to processing cost and challenges. The conventional method for manufacturing lamellar ceramic-metal composites is melt-infiltration of the metal phase into the gaps of the ceramic scaffold. The smaller the gap, the more difficult the infiltration. Because of the poor wetting between most metals and ceramics, the process requires high pressure and temperature to squeeze the molten metal into the gaps in the ceramic phase. This project aims at developing manufacturing strategies inspired by nature to enable low-cost fabrication of ceramic-metal composites. Natural materials such as bone and the nacreous part of sea-shells have developed structural composites, using a set of rather ordinary constituents, which exhibit extraordinary mechanical properties. For example, seashells convert a brittle ceramic material to a super-tough material (nacre) by incorporation of around 5% polymer, in a layered ?brick-and-mortar? microstructure. The scientific community has been very successful in identifying the design principles of biological structural composites. However, manufacturing knowledge gaps persist. These include the challenge of infiltration of small gaps between ceramic bricks, the challenge of obtaining ductile (while strong) mortars; the challenge in design of proper (metal-ceramic) interfaces; and the high cost. Low-cost processes for fabrication of metal−ceramic composites can substantially increase their applications in various industries including automotive, aerospace, oil and defense, in products such as high performance wear-resistance parts, cutting tools, lightweight structural composites, and aero-engine components. For these reasons, the project directly impacts American economic welfare and national security. The educational objective of the project is focused on increasing the diversity in nanotechnology- STEM through ?NanoExplorer? summer program for high school students, with particular emphasis on female students, including Latinos. The goal of this research is to investigate the mechanisms underlying processing and manufacturing of ceramic composites for damage-tolerant structural applications. The project is focused on understanding infiltration of nanotwinned metals into nano-gaps (100 nm) of a 3-dimensional porous ceramic scaffold by pulsed electrodeposition. A conservative estimate shows that the energy consumption in this process is more than 200-fold smaller than the conventional molten metal infiltration process. The liquid electrolyte in electrodeposition has much less viscosity compared to molten metals, and hence can effectively penetrate into the small gaps between the ceramic bricks. A class of metals that defeat the trade-off between strength and toughness are ?nanotwinned? metals. Nanotwinned metals have high density of coherent twin boundaries, which has been shown to enhance both strength and ductility. Pulsed electrodeposition is one of the primary methods of synthesis of nanotwinned metals. To address the metal-ceramic interface challenge, electroless deposition of a thin metal layer on ceramic bricks is planned, which will result in uniform coating, as well as strong adhesion between ceramics and metals. This research, if successful, will result in new fundamental knowledge in following subjects: (i) Growth mechanism and microstructure of nanotwinned metals directly synthesized by pulsed electrodeposition into a laminated ceramic scaffold; (ii) Kinetics of pulsed electrodeposition process in nano-channels (100 nm); and (iii) Infiltration of a nano-porous ceramic scaffold by electrodeposition.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.