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其在核能、空间和其他极端条件下的应用至关重要。金属合金可以通过分散细小的(纳米级)氧化物颗粒来强化。氧化钇纳米粒子极大地增强了这种氧化物弥散强化(Ods)合金的热机械性能和抗辐射性能。了解这些纳米粒子在极端环境下的极高稳定性在科学上是具有挑战性的，但在技术上是必要的，以便开发具有增强性能的先进结构材料。通过实验工作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促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，通过RPI和加州大学戴维斯分校的各种计划，让代表性不足的学生，特别是女工程师，进入科学和工程领域。这一基本认识将有助于辐射效应与核反应堆材料双水平课程的发展。在RPI。该项目的成果将通过国内和国际会议报告向更广泛的受众传播。技术研究人员在实验和原子模拟的协同基础上，RPI和加州大学戴维斯分校的研究小组将致力于对分散的氧化物纳米颗粒在高温和强辐射条件下的相稳定性进行科学理解。合成了Y-Ti-O纳米粒子(如Y2Ti2O7和Y2TiO5)，并将其置于不同的辐照条件和不同的温度下，并用透射电子显微镜(TEM)技术对其形貌和微观结构进行了表征。量热测量将研究Y-Ti-O纳米粒子的热力学稳定性随尺寸、照射和温度的变化。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，将探索辐射和温度对氧化物纳米颗粒结构演化及其缺陷行为的协同效应。这一基本认识将揭示控制Y-Ti-O纳米颗粒相稳定性和缺陷行为的潜在物理和化学因素，并为开发纳米结构材料在强辐射和高温极端条件下的行为预测模型奠定基础。在这些基本认识的基础上，新的科学将发展到设计材料加工中的策略，以利用氧化物纳米颗粒来强化合金。

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.