Coupled Nucleation, Nanostructure Formation and Hydrogen Storage in Metallic Glasses and Quasicrystals

金属玻璃和准晶体中的耦合成核、纳米结构形成和储氢

• 批准号: 0606065
• 负责人: Kenneth Kelton
• 金额: $ 32.4万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-05-15 至 2010-04-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0606065&HistoricalAwards=false
• 关键词: Coupled; Nucleation; Nanostructure; Formation; Hydrogen

TECHNICAL: Nucleation processes are more complex than often assumed, and proper account must be taken of the coupling between the stochastic fluxes of long-range diffusion and interfacial attachment. Recent studies, including those by PI indicate that order-parameter fluctuations such as those that underlie chemical, structural, and magnetic ordering can also couple with the order parameter fluctuations associated with nucleation. In addition to their basic interest, these results demonstrate that enhanced nanostructural refinement is possible by an improved understanding of this nucleation behavior. To better understand coupled process in nucleation and their potential for improved microstructure refinement, this project will determine the local atomic structure of select Ti/Zr-based, Co/Fe-based and Mg-based metallic glasses by wide and small angle x-ray diffraction; high resolution, energy filtered and fluctuation transmission electron microscopy; EXAFS; and atom probe measurements. This data will be correlated with glass formation and the crystallization kinetics, determined by differential scanning calorimetry and electrical resistivity measurements and by TEM based studies of time-dependent nucleation. Research will also continue to probe the influence of diffusion on nucleation behavior. The cycling characteristics and origin of the high-pressure plateau will be determined for bulk and nanostructured i(TiZrNi) to evaluate its potential usefulness as a hydrogen storage material. NON-TECHNICAL: The results from these studies will be of broad basic and technological interest including hydrogen storage, a deeper understanding of phase transitions and improved control over nanostructure production. The Ti/Zr quasicrystals could help facilitate the transition to a hydrogen-based transportation system. The research has a significant educational importance, providing training to graduate and undergraduate students, and experience to local high school students in the theoretical and experimental methods of materials science. PI and his graduate students will give presentations of research results to the students and teachers and work directly with the students to expose them to the possibilities for scientific careers.

技术：成核过程比经常假设的过程更为复杂，必须正确考虑远程扩散和界面附着的随机通量之间的耦合。最近的研究，包括PI的研究表明，有序参数的波动，例如基于化学，结构和磁有序的基础的研究也可以与与成核相关的阶参数波动相结合。除了基本的兴趣外，这些结果还表明，通过对这种成核行为的了解，可以增强纳米结构的完善。为了更好地了解成核中的耦合过程及其改善微观结构细化的潜力，该项目将通过宽和小角度X射线衍射来确定基于选择的Ti/Zr，基于CO/FE的基于CO/FE的局部原子结构；高分辨率，能量过滤和波动透射电子显微镜； exafs;和原子探针测量。该数据将与玻璃形成和结晶动力学相关，该动力学由差异扫描量热法和电阻率测量以及TEM基于时间依赖性成核的研究确定。研究还将继续探测扩散对成核行为的影响。将确定大量和纳米结构I（Tizrni）的循环特性和起源，以评估其作为氢存储材料的潜在有用性。非技术性：这些研究的结果将具有广泛的基本和技术兴趣，包括氢存储，对相变的更深入了解以及对纳米结构生产的控制。 Ti/Zr准晶体可以帮助促进过渡到基于氢的运输系统。这项研究具有重要的教育意义，为研究生和本科生提供培训，并以理论和实验性材料科学方法的方式为当地的高中生提供了经验。 PI和他的研究生将向学生和老师提供研究结果的演讲，并直接与学生合作，使他们了解科学职业的可能性。