STTR Phase I: Biomimetically Engineered Ceramics

这个小型企业技术转移第一阶段项目旨在开发基于损伤容限海壳微体系结构的工程陶瓷仿生结构。工程陶瓷材料损伤容限差，在应力作用下会出现灾难性的破坏模式，限制了其在结构中的应用。在极端条件下，陶瓷通常只起到隔热或化学屏障的作用。通过相变增韧、针状颗粒和纤维整体(FMS)等工程结构，部分陶瓷的损伤容忍度已有所提高。通过模仿Strombus Gigas(海贝壳)的微体系结构，可以实现显著的进一步收益。海壳的多尺度结构将被复制到由氮化硅和氮化硼组成的模型工程陶瓷系统中，方法是借用并大量建立在制造FMS时使用的技术，包括热塑性变形和组装。将对通过这些复杂体系结构的裂纹扩展进行建模，以帮助指导该过程的发展。将对工程陶瓷的微观结构、机械和热学性能进行表征。这项研究将确定所提出的热塑性变形/组装技术的可行性，以设计一种三阶仿生陶瓷材料，该材料的断裂功预计将是可比FM的两倍以上。该项目的更广泛的影响/商业潜力将是开发高损伤容限陶瓷，这将增加其在工程应用中的实用性，并验证生物灵感材料工程。仿生陶瓷将在很大程度上改善现有陶瓷系统的损伤容限，因此将引起制造业、军事/航空航天和医疗等许多行业的极大兴趣。没有类似的技术可以结合陶瓷的优点(低密度、热稳定性、高硬度)而没有缺点(损害容忍度较差)。陶瓷和金属基复合材料比块状陶瓷具有更好的可靠性，但价格昂贵，往往达不到设计要求。超韧性陶瓷将在医疗植入物中产生更好的性能，保持美国制造业的领先地位，并促进先进的汽车技术。通过创造既能满足热要求又能满足结构要求的材料，这项技术将创造出更多多功能陶瓷。此外，该项目将导致更好地理解裂纹通过损伤容限层次化结构的扩展。最后，该项目将涉及维拉诺瓦大学的本科生和研究生，研究的关键成果将在多学科会议和期刊上传播。

This Small Business Technology Transfer Phase I project seeks to develop biomimetic structures in engineering ceramics based on the damage-tolerant sea shell micro-architecture. Poor damage tolerance of engineering ceramics leads to catastrophic failure modes under stress, which restricts their structural utility. In extreme conditions, ceramics generally function only as a thermal or chemical barrier. Gains in damage tolerance have been made in select ceramics via transformation toughening, acicular grains, and engineered architectures such as Fibrous Monoliths (FMs). Significant further gains can be achieved by mimicking the micro-architecture of the Strombus Gigas (sea shell). The multiscale architecture of the sea shell will be replicated in a model engineering ceramic system comprised of silicon nitride and boron nitride by borrowing and significantly building on the techniques used in making FMs, including thermoplastic deformation and assembly. Modeling of crack propagation through these complex architectures will be performed to help guide the development of the process. The microstructural, mechanical, and thermal properties of the engineered ceramics will be characterized. This research will establish the viability of the proposed thermoplastic deformation/assembly techniques to engineer a third-order biomimetic ceramic material which is expected to have a work-of-fracture more than twice as large as a comparable FM.The broader impact/commercial potential of this project will be the development of highly damage-tolerant ceramics that will increase their utility in engineering applications and validate bio-inspired materials engineering. The biomimetic ceramics will improve on the damage tolerance of existing ceramic systems by a significant margin and therefore will be of great interest to many industries: manufacturing, military/aerospace, and medical. No comparable technology exists which combines the benefits of ceramics (low density, thermal stability, high hardness) without their disadvantages (poor damage tolerance). Ceramic- and metal-matrix composites offer better reliability than bulk ceramics, but are expensive and often fall short of design requirements. Ultra tough ceramics will produce better performance in medical implants, maintain American manufacturing leadership, and promote advanced vehicle technology. By creating materials which can meet both thermal and structural requirements, this technology will create more multi-functional ceramics. Additionally, this project will lead to a better understanding of crack propagation through damage-tolerant hierarchical structures. Finally, the project will involve undergraduate and graduate students at Villanova University, and key results of the research will be disseminated in multidisciplinary conferences and journals.