Collaborative Research: DMREF: Topologically Designed and Resilient Ultrahigh Temperature Ceramics

超高温陶瓷是一类具有极高熔融温度的材料。因此，它们在包括高超音速飞行、核聚变反应堆和聚光太阳能在内的极端环境应用中具有很大的前景。然而，它们在低温下易碎，这对功能产生了负面影响。相反，这些材料在超高温度下变形太大。通常，这些属性中的一个可以以牺牲另一个为代价来改进，这使得优化变得困难。这个设计材料来革新和工程我们的未来（DMREF）项目将开发一种新方法，通过设计和制造特定的晶体结构和独特的微观结构，同时改善这些材料的低温和高温性能。作为这项研究工作的一部分，下一代科学家和工程师将以跨学科的方式接受培训，因为他们将共同努力，弥合不同的学科。这种教育将通过一个活跃的高中和本科暑期项目来扩大，该项目将确定STEM中服务不足的人口统计数据。此外，该项目将对中学教师进行材料科学，特别是陶瓷的教育，为他们提供将这些信息整合到物理，化学和物理科学课程中的工具集，从而大大扩大科学产生的影响。该项目的总体目标是设计出既能在低温下抗断裂又能在高温下抗蠕变的超高温陶瓷。这将通过自下而上的方法设计陶瓷来实现，该方法利用材料自身的自然长度尺度和化学成分来稳定低对称的晶体结构，这些晶体结构的细长形状融合在一起，形成互锁的材料微观结构。计算工具的组合，包括第一性原理和机器学习，将集成到实验方法中，直接合成定制的粉末形态，其中结构和性能的特征。通过这种相互作用和结果的迭代循环，特定的金属和非金属物种将被识别和设计，以促进具有连锁形态的所需阶段。通过同时提高我们的超高温陶瓷的韧性和抗变形能力，这项研究将使在极端环境下使用的技术取得进步，同时在多学科教育环境中为学生提供独特的培训。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Ultrahigh temperature ceramics are a class of materials with exceptionally high melting temperatures. Consequently, they hold great promise for extreme environment applications that include hypersonic flight, nuclear fusion reactors, and concentrated solar power. However, they are brittle at low temperatures, which negatively impacts functionality. Conversely, these materials deform too much at ultrahigh temperatures. Usually, one of these properties can be improved at the expense of the other, making optimization difficult. This Designing Materials to Revolutionize and Engineer our Future (DMREF) project will develop a new method to simultaneously improve both the low temperature and high temperature properties of these materials by devising a means to design and manufacture specific crystal structures and unique microstructures. As part of this research effort, the next generation of scientists and engineers will be trained in a cross-disciplinary manner as they work together to bridge different disciplines. This education will be expanded through an active high school and undergraduate summer program that identifies underserved demographics in STEM. Additionally, this project will educate secondary school teachers about materials science, and specifically ceramics, giving them the toolsets to integrate such information into physics, chemistry, and physical science courses dramatically broadening the impact of the science generated.The overarching goal of this project is to design ultrahigh temperature ceramics that are both resistant to fracture at low temperatures and resilient against creep at high temperature. This will be achieved by designing the ceramic from a bottom-up approach that utilizes the materials’ own natural length scales and chemistry to stabilize low symmetry crystal structures whose elongated shapes fit together creating an interlocked material microstructure. A combination of computational tools, including first principles and machine learning, will be integrated into experimental methods that directly synthesize customized powder morphologies where the structure and property performance is characterized. Through this iterative loop of interactions and outcomes, specific metal and nonmetal species will be identified and designed to promote desired phases with interlocking morphologies. By simultaneously improving toughness and deformation resistance in our ultrahigh temperature ceramics, this research will enable the advancement of technologies for use at extreme environments, while providing unique training for students in a multidisciplinary educational environment.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.