Materials World Network: Dual Composite Ceramics for Improved Properties

非技术描述：该项目是超高温陶瓷领域两个领先的研究小组之间的合作，即意大利法恩扎的陶瓷科学与技术研究所(ISTEC)和密苏里州罗拉的密苏里科技大学。ISTEC的团队包括Frederic Monteverde博士和Diletta Sciti博士，他们分别由意大利国家理查委员会(CNR)资助。联合努力的重点是硼化物基陶瓷的加工和微观结构的基本方面，以改善其高温力学性能。硼化物陶瓷，如二硼化锆，目前能够承受一定温度范围内的持续机械载荷，但在极端载荷和正在研究和开发的极端热机械条件下灾难性地失效。应用包括用于高超声速飞行的热保护系统、用于核反应堆的安全壳材料和燃料形式、用于机械加工的高速刀具以及用于金属生产的超高温耐火材料。该项目的重点是开发一种双重复合结构，旨在创造一种在高温和极端环境下具有优异机械性能的结构陶瓷的新范例。在极端环境中的商业应用中使用双重复合陶瓷的能力，将提高未来系统的能效和可持续性，如高超声速飞机和熔融金属容器。技术细节：利用ISTEC研究小组在二硼化硅陶瓷方面的综合专业知识和密苏里州S&T研究小组的分级陶瓷复合材料的加工和性能专业知识，该项目的目标是开发具有改进高温机械性能的双重复合陶瓷的新范例。与二硅化钼一起进行液态烧结的二硼化锆正被用作双重复合陶瓷的基础成分，尽管这一概念广泛适用于任何热力学上兼容的材料体系。通过实验研究、基于物理模型和分析表征技术，研究了在多个长度尺度(即双重复合结构)上控制陶瓷的结构和微结构对硼化物基陶瓷高温力学行为的影响。该项目是基于全球开发用于极端环境应用的新陶瓷材料的需求而适时进行的。此外，研究成果有可能将最先进的硼化物陶瓷转化为能够延长陶瓷寿命和在极端环境中应用陶瓷的温度的陶瓷，包括高超声速飞行器、核反应堆、熔融金属和玻璃安全壳等。最后，用于极端环境的陶瓷材料是一个高度专业化的研发领域，迫切需要更多训练有素的科学家和工程师来领导未来的研究工作。该项目通过促进来自两个机构的年轻、代表性不足的研究人员的交流，以及通过直接培训一名研究生和两名本科生在极端环境中使用的陶瓷的加工、测试和表征，直接影响了陶瓷领域的这一领域。

NON-TECHNICAL DESCRIPTION: This project is a collaboration between two of the leading research groups in the area of ultra-high temperature ceramics, namely the Institute for the Science and Technology for Ceramics (ISTEC) in Faenza, Italy and the Missouri University of Science and Technology in Rolla, MO. The team at ISTEC includes Dr. Frederic Monteverde and Dr. Diletta Sciti who are funded separately by the Consiglio Nazionale delle Ricerche (CNR) in Italy. The focus of the combined effort is on fundamental aspects of processing and microstructure of boride-based ceramics to improve their mechanical properties at elevated temperature. Boride ceramics, such as zirconium diboride, are currently capable of withstanding sustained mechanical loads over a range of temperatures but fail catastrophically under extreme loads and under the extreme thermomechanical conditions for which they are being researched and developed. Applications include thermal protection systems for hypersonic flight, containment materials and fuel forms for nuclear reactors, high-speed cutting tools for machining, and ultra-high temperature refractories for metal production. The focal point of this project is the development of a dual composite architecture designed to create a new paradigm of structural ceramics with superior mechanical properties at elevated temperatures and in extreme environments. The ability to utilize dual composite ceramics in commercial applications, in extreme environments, will provide improvements in both energy efficiency and sustainability of future systems such as hypersonic aircraft and molten metal containment.TECHNICAL DETAILS: Utilizing the combined expertise of the research group at ISTEC in diboride-silicide ceramics and the processing and properties of hierarchical ceramic composites expertise of the research group at Missouri S&T, the goal of the project is the development of a new paradigm of dual composite ceramics with improved elevated temperature mechanical properties. Zirconium diboride that is liquid phase sintered with molybdenum disilicide is being used as a base composition for the dual composite ceramics, although the concept is broadly applicable to any thermodynamically compatible material system. The role of controlling the structure and microstructure of ceramics at multiple length scales (i.e., a dual composite architecture) on the elevated temperature mechanical behavior of boride-based ceramics is being investigated using experimental studies, physics-based models, and analytical characterization techniques. The project is timely based on the global need to develop new ceramic materials for applications in extreme environments. Furthermore, the outcome of the research has the potential to transform state of the art boride ceramics into ceramics capable of extending the lifetime and use temperature of ceramics for applications in extreme environments, including hypersonic flight vehicles, nuclear reactors, molten metal and glass containment vessels, and others. Finally, ceramic materials for extreme environments is an area of research and development that is highly specialized and in dire need of more trained scientists and engineers to lead future research efforts. The project is directly impacting this area of the ceramic field by facilitating the exchange of young, underrepresented researchers from both institutions and by directly training a graduate student and two undergraduate students in the processing, testing, and characterization of ceramics for use in extreme environments.