CAREER: Computer Assisted Experimental Phase Equilibria (CAEPE)

非技术描述：相图是用于辅助和指导几乎所有材料设计的流程图。在陶瓷工程中，已经绘制了许多二组分和三组分体系的相图(组分可以是元素，如Zr-C，也可以是元素组，如ZRC-NbC)。然而，随着系统中组件数量的增加，由于所涉及的复杂性，可用相图的数量会减少。此外，高温陶瓷相图数据通常由于其超高熔点而无法获得。一些碳化物直到~4000˚C才会熔化。该项目通过将计算方法与先进的超高温实验技术相结合，在超高温(~4000˚C)下更有效地绘制多组分(5组分)相图，从而解决了这两个问题。这些多组分的超高温相图将对材料工程师开发用于高超声速、核(裂变和聚变)反应堆和航天器屏蔽的新一代超高温材料至关重要。此外，该项目正在建立跨年龄和人口结构的导师链，以促进不同的下一代科学和工程领导者。技术细节：本研究的核心重点是开发一种计算机辅助实验相平衡(CAEPE)方法，该方法利用相图计算(CALPHAD)建模，并结合贝叶斯推理和马尔可夫链蒙特卡罗进行误差量化，从而实现战略性定向实验。核心实验包括使用一系列先进的合成、量热、衍射/散射和空气动力学悬浮激光加热技术收集从室温到超高温(~4000˚C)的热力学和物理数据。这些实验数据对于加工和设计用于高超声速、核(裂变和聚变)反应堆和航天器屏蔽的下一代超高温材料系统是必不可少的。CAEPE方法针对的第一个材料系统是5组分的单碳化物ZRC-NBC-HFC-TaC-TiC伪五元系统，因为它包含已知的最高熔点材料。最后，这个项目将培养研究生使用综合计算材料工程(ICME)的方法进行思考，并培训他们具有开创性的、先进的高温实验技术。这些技能将对未来推动超高温材料设计极限的材料工程师至关重要。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

NON-TECHNICAL DESCRIPTION: Phase diagrams are the process maps that are used to assist and direct nearly all materials design. In ceramics engineering, many phase diagrams for two and three component systems (components can be elements; such as Zr-C, or groups of elements; such as ZrC-NbC) have been developed. However, as the number of components in the system increases, the number of available phase diagrams decreases due to the complexity involved. Additionally, high temperature ceramic phase diagram data is typically unavailable due to their ultra-high melting points. Some carbides do not melt until ~4000 ˚C. This project remedies both of these issues by integrating computational methods with advanced ultra-high temperature experimental techniques to more efficiently develop multi-component (5 component) phase diagrams at ultra-high temperatures (~ 4000 ˚C). These multi-component ultra-high temperature phase diagrams will be essential for materials engineers to develop next generation ultra-high temperature materials for applications in hypersonics, nuclear (fission and fusion) reactors and shielding for space craft. In addition, this project is building mentoring chains across age and demographics to facilitate diverse next generation science and engineering leaders. This is achieved through a variety of outreach activities that connect high school students to university students (at the undergraduate and graduate level), and university students to professionals in industry.TECHNICAL DETAILS: The core focus of this research is developing a computer-assisted experimental phase equilibria (CAEPE) methodology that utilizes CALculation of PHAse Diagrams (CALPHAD) modelling in combination with Bayesian inference and Markov-Chain Monte-Carlo for error quantification that enable strategic targeted experiments. Core experiments involve collecting thermodynamic and physical data from room temperature to ultra-high temperatures (~4000 ˚C) using a series of advanced synthesis, calorimetry, diffraction/scattering, and aerodynamic levitation laser heating techniques. This experimental data is essential for processing and engineering next generation ultra-high temperature materials systems for applications in hypersonics, nuclear (fission and fusion) reactors and shielding for spacecraft. The first material system to be targeted with CAEPE approach is the 5-component monocarbide ZrC-NbC-HfC-TaC-TiC pseudo-quinary system, as it contains the highest melting point material known. Finally, this project will prepare graduate students to think using an integrated computation materials engineering (ICME) approach, and train them on pioneering, advanced high temperature experimental techniques. These skills will be essential for the future materials engineers that will push limits of ultra-high temperature materials design.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.