Collaborative research: experimental and computational study of structure and thermodynamics of rare earth oxides above 2000 C

合作研究：2000℃以上稀土氧化物结构和热力学的实验和计算研究

• 批准号: 1835939
• 负责人: Axel van de Walle
• 金额: $ 21.38万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-07-01 至 2022-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1835939&HistoricalAwards=false
• 关键词: Collaborative; research; experimental; computational; study

NON-TECHNICAL DESCRIPTION: Materials that can withstand ultrahigh temperatures are important to ceramic processing, aerospace, and nuclear applications. Oxides containing rare earth elements have high melting points, do not evaporate easily, and are generally chemically unreactive. This refractory nature favors high temperature applications, but at the same time makes the determination of their heat and energy relationships (thermodynamic) properties challenging, and current data are incomplete. Such data are essential for prediction of material stability or degradation during use in both simple and complex systems in a variety of extreme environments (such as high-temperature or high-pressure environments). New experimental and computational approaches to determine thermodynamics above 2000 degrees C form the primary focus of the project, which represents collaboration between Navrotsky's group at University of California at Davis performing thermochemical measurements and structural studies, and van de Walle's group at Brown University undertaking calculations and phase diagram assessments. The project provides university-level students an opportunity to participate in state-of-the-art experimental and computational research applied to high temperature processes. TECHNICAL DETAILS: The goals are to develop, test and apply new methodology (i) to determine temperatures and heats of phase transitions (both solid-solid and melting) of rare earth oxides and oxycarbides above 2000 degrees C, (ii) to measure structural parameters, including thermal expansion and volume change upon phase transition by synchrotron X-ray diffraction on levitated samples above 1500 degrees C, (iii) to calculate high-temperature thermodynamic properties using ab initio density functional theory (with hybrid functionals) and molecular dynamics in conjunction with statistical mechanical techniques, and (iv) to generate a unified picture, based on both theory and experiment, of thermodynamic properties, to be made publicly available for use in calculation of phase diagrams (CalPhaD) modeling and other applications. The combination of calorimetry, X-ray diffraction, and computation provides both needed thermodynamic data and physical insight into the properties of refractory rare earth oxides, with extensions into more complex systems. In addition to international journals and meetings on ceramics, dissemination is taking place through smaller focused conferences and lectures on their websites. Newly developed ab initio computational techniques are being integrated within the widely used and freely distributed ATAT software.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.

非技术描述：能够承受超高温的材料对于陶瓷加工、航空航天和核应用非常重要。含有稀土元素的氧化物熔点高，不易蒸发，一般不发生化学反应。这种耐火特性有利于高温应用，但同时使得确定其热能关系（热力学）特性具有挑战性，并且当前数据不完整。此类数据对于预测材料在各种极端环境（例如高温或高压环境）的简单和复杂系统中使用期间的稳定性或降解至关重要。确定 2000 摄氏度以上热力学的新实验和计算方法构成了该项目的主要焦点，该项目代表了加州大学戴维斯分校 Navrotsky 团队进行热化学测量和结构研究，与布朗大学 van de Walle 团队进行计算和结构研究之间的合作。相图评估。该项目为大学学生提供了参与高温过程最先进的实验和计算研究的机会。技术细节：目标是开发、测试和应用新方法 (i) 确定 2000 摄氏度以上稀土氧化物和碳氧化物的相变温度和热量（固-固和熔化），(ii) 测量结构参数，包括通过同步加速器 X 射线衍射对 1500 摄氏度以上的悬浮样品进行相变时的热膨胀和体积变化，(iii) 使用 ab 计算高温热力学性质从头密度泛函理论（混合泛函）和分子动力学与统计力学技术相结合，以及（iv）基于理论和实验生成热力学性质的统一图景，公开用于计算相图 (CalPhaD) 建模和其他应用。 量热法、X 射线衍射和计算的结合提供了所需的热力学数据和对难熔稀土氧化物特性的物理洞察，并扩展到更复杂的系统。除了关于陶瓷的国际期刊和会议外，还通过其网站上的小型重点会议和讲座进行传播。新开发的从头计算技术正在被集成到广泛使用和免费分发的 ATAT 软件中。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

Software tools for thermodynamic calculation of mechanically unstable phases from first-principles data

根据第一原理数据对机械不稳定相进行热力学计算的软件工具

• DOI: 10.1016/j.cpc.2019.01.008
• 发表时间: 2024-09-14
• 期刊: Comput. Phys. Commun.
• 作者: S. Kadkhodaei;A. Walle
• 通讯作者: A. Walle

A simple method for computing the formation free energies of metal oxides

计算金属氧化物形成自由能的简单方法

• DOI: 10.1016/j.commatsci.2021.110692
• 发表时间: 2021-10-01
• 期刊: Computational Materials Science
• 影响因子: 3.3
• 作者: Hantong Chen;Qi;S. Ushakov;A. Navrotsky;A. Walle
• 通讯作者: A. Walle

Energetics of melting of Yb2O3 and Lu2O3 from drop and catch calorimetry and first principles computations

通过滴捕量热法和第一原理计算熔化 Yb2O3 和 Lu2O3 的能量

• DOI: 10.1016/j.jct.2019.01.008
• 发表时间: 2019-01
• 期刊: The Journal of Chemical Thermodynamics
• 作者: Fyhrie, Matthew;Hong, Qi;Kapush, Denys;Ushakov, Sergey V.;Liu, Helena;van de Walle, Axel;Navrotsky, Alexandra
• 通讯作者: Navrotsky, Alexandra

Reentrant melting of sodium, magnesium, and aluminum: General trend

钠、镁、铝的重入熔化：总体趋势

• DOI: 10.1103/physrevb.100.140102
• 发表时间: 2019-10-17
• 期刊: Physical Review B
• 影响因子: 3.7
• 作者: Qi;A. van de Walle
• 通讯作者: A. van de Walle

The United States COVID-19 Forecast Hub dataset

美国 COVID-19 预测中心数据集

• DOI: 10.1038/s41597-022-01517-w
• 发表时间: 2022-12
• 期刊: Scientific Data
• 影响因子: 9.8
• 作者: Cramer, Estee Y.;Huang, Yuxin;Wang, Yijin;Ray, Evan L.;Cornell, Matthew;Bracher, Johannes;Brennen, Andrea;Rivadeneira, Alvaro J.;Gerding, Aaron;House, Katie;et al
• 通讯作者: et al