Collaborative Research: Atomistic Mechanisms of Stabilizing Oxide Nanoparticles in Oxide-dispersion Strengthened Structural Materials

非技术描述：材料在高温和辐射条件下的存活对于它们在极端条件下在核能、空间和其他应用中的应用至关重要。金属合金可以通过分散小的（纳米级）氧化物颗粒来强化。钇钛氧化物纳米颗粒极大地增强了这种氧化物弥散强化（ODS）合金的热机械和抗辐射性能。了解这些纳米颗粒在极端环境下的异常高稳定性，以开发具有增强性能的先进结构材料，在科学上具有挑战性，但在技术上是必要的。通过实验努力和多尺度计算机模拟的协同作用，RPI和加州大学戴维斯分校的研究人员将推进对这种纳米颗粒的转化和结构演变的理解和控制。该研究计划将培养在辐射效应和先进结构材料开发的关键领域工作的研究生和本科生。将作出特别努力，让代表性不足的学生，特别是女工程师，通过在RPI和加州大学戴维斯分校的各种方案进入科学和工程。这些基本认识将有助于发展一个双层次的课程？辐射效应和核反应堆材料在RPI。该项目的研究成果将通过国内和国际会议的演讲向更广泛的受众传播。技术支持建立在实验和原子模拟的协同作用基础上，RPI和加州大学戴维斯分校的研究小组将致力于对高温和强辐射条件下分散氧化物纳米颗粒的相稳定性的科学理解。Y-Ti-O纳米颗粒（例如，Y2 Ti 2 O 7和Y2 TiO 5）将被合成并暴露于使用强离子束的不同辐照条件和不同温度，并且将通过透射电子显微镜（TEM）技术彻底表征形貌和微观结构。量热测量将研究Y-Ti-O纳米颗粒的热力学稳定性作为尺寸、辐照和温度的函数。原子计算机模拟，包括第一性原理计算，经典分子动力学和动力学蒙特卡罗模拟，将探测辐射和温度对氧化物纳米颗粒的结构演化及其缺陷行为的协同效应。这种基本的理解将揭示控制Y-Ti-O纳米颗粒的相稳定性和缺陷行为的基本物理和化学，并为开发纳米结构材料在强辐射和高温的极端条件下如何表现的预测模型奠定基础。基于这样的基本认识，新的科学将发展到设计材料加工策略，通过氧化物纳米颗粒强化合金。

NON-TECHNICAL DESCRIPTION: The survival of materials under conditions of high temperature and radiation is crucial to their application in nuclear energy, space, and other applications under extreme conditions. Metal alloys can be strengthened by the dispersion of small (nanoscale) oxide particles. Yttrium titanium oxide nanoparticles greatly enhance the thermo-mechanical and radiation-resistant properties of such oxide-dispersion strengthened (ODS) alloys. It is scientifically challenging but technologically necessary to understand the exceptionally-high stability of these nanoparticles under extreme environments in order to develop advanced structural materials with enhanced performance. By synergy of experimental efforts and multi-scale computer simulations, the researchers at RPI and UC Davis will advance the understanding and control of transformation and structural evolution of such nanoparticles. This research program will train both graduate and undergraduate students working in key fields of radiation effects and the development of advanced structural materials. Special efforts will be made to involve underrepresented students, particularly woman engineers, into science and engineering through various programs at RPI and UC Davis. The fundamental understanding will contribute to the development of a dual-level course of ?radiation effects and nuclear reactor materials? at RPI. Findings of this project will be disseminated to a wider audience through national and international conference presentations.TECHNICAL DETAILSBuilding on a synergy of experiments and atomistic simulations, the groups at RPI and UC Davis will target a scientific understanding of the phase stability of dispersed oxide nanoparticles under high temperature and intense radiation conditions. Y-Ti-O nanoparticles (e.g., Y2Ti2O7 and Y2TiO5) will be synthesized and exposed to different irradiation conditions using intense ion beams and to different temperatures, and the morphology and microstructure will be characterized thoroughly by transmission electron microscopy (TEM) techniques. Calorimetric measurements will investigate the thermodynamic stability of Y-Ti-O nanoparticles as a function of size, irradiation, and temperature. Atomistic computer simulations, including first principles calculations, classical molecular dynamics and kinetic Monte Carlo simulations, will probe synergistic effects of radiation and temperature on the structural evolution of oxide nanoparticles and their defect behavior. This fundamental understanding will reveal the underlying physics and chemistry that govern phase stability and defect behavior of Y-Ti-O nanoparticles and establish the basis for developing predictive models of how nanostructured materials behave under extreme conditions of intense radiation and high temperature. Based on such fundamental understanding, new science will evolve to design strategy in materials processing for strengthening of alloys by oxide nanoparticles.