GOALI: Dynamics of Layered, Multifunctional Systems with Evolving Structure

非技术描述：召集了一个跨学科的学术/行业团队，对用于燃气轮机部件的热和环境保护的多层多功能系统的基本方面进行研究。这些材料系统在发动机效率方面提供了巨大的改进，对国家能源和交通部门的经济和环境影响以及美国工业的全球竞争力都有好处。由于对这些多材料非平衡系统在暴露于现代技术中遇到的最恶劣的环境之一后如何随时间演变的理解不足，目前阻碍了这一承诺的实现。研究小组的目标是通过关注层和界面的化学，内部结构和形态之间的基本联系，它们随时间的演变，对特性的影响以及最终损害系统完整性并导致失败的相关机制来推进这种理解。该计划提供了独特的教育机会，(i)激励学生在技术重要问题的背景下学习本学科的科学基础，（ii）作为跨学科团队的成员，其中包括来自该领域世界领先公司（通用电气）的科学家，与具有不同背景和专业知识的学者合作。（iii）有机会在一流的企业研究中心（通用电气全球研究中心）实习。随着研究变得越来越全球化，学生在国外做研究的经验被认为是非常宝贵的。该项目为欧洲、拉丁美洲和环太平洋国家的合作机构提供了这样的机会，包括位于班加罗尔的GE-GRC。该计划将受益于参与大学优秀的外展基础设施，以及研究人员在研究中涉及本科生和代表性不足群体成员的可靠记录。该项目的基本性质，其对美国经济至关重要的技术的预期影响，以及为学生提供的教育丰富经验，与美国国家科学基金会及其赞助项目的目标完全一致。技术细节：该计划的总体目标是发展对受燃气涡轮发动机典型极端环境影响的分层系统结构演变动力学的基本理解，以及这些系统如何影响系统性能。建立控制层内和层间物理化学现象的基本原理，将使设计在更高温度下运行的下一代涡轮系统的改进保护概念成为可能。所产生的信息还将有助于验证和改进用于设计和耐久性评估的系统级模型。该研究旨在通过将组件/层功能与导致其退化的进化过程结合起来，提炼出对技术重要系统具有关键影响的现象。由于系统的复杂性和层的规模，新的高分辨率探头占据了核心地位。科学进步是在以下五个主题中设想的。(a)多掺杂体系中亚稳相分解和聚类引起的难熔氧化物的相演化。(b)氧化物的表面扩散，包括它对掺杂剂的依赖，以及它对有织构柱状结构烧结的影响。(c)氧化铝热生长引起的应力和变形的演变。(d)层间扩散对相演化、体积应变和应力诱发转变的影响；包括结构相容扩散屏障的行为。(e)结构演变对关键性能的影响，特别是对各层和界面的韧性、高温下的本构行为以及氧化物的光学和热性能的影响。项目旨在促进合作，特别是学生和博士后之间的合作，并促进共同建议。校外体验，特别是在GE-GRC，让学生有机会使用独特的设施，并与工业科学家进行互动，这有助于学生了解他们的论文研究如何为该领域的整体努力和进步做出贡献。资助：该项目由国际科学与工程办公室、工程理事会和数学与物理科学理事会的陶瓷项目共同资助。

NON-TECHNICAL DESCRIPTION: An interdisciplinary academic/industry team has been convened to perform research on fundamental aspects of layered multifunctional systems used for the thermal and environmental protection of gas turbine components. These material systems offer quantum-leap improvements in engine efficiency with attendant benefits to the economics and environmental impact of the national energy and transportation sectors, as well as to the global competitiveness of the US industry. Fulfillment of this promise is currently hindered by inadequate understanding of how these multi-material non-equilibrium systems evolve over time upon exposure to one of the harshest environments encountered in modern technology. The research team aims to advance this understanding by focusing on the fundamental connections between the chemistry, internal structure and morphology of the layers and interfaces, their evolution over time, the impact on properties and the relevance to mechanisms that eventually compromise the integrity of the system and lead to failure. The program provides unique educational opportunities by (i) motivating students to learn the scientific foundation of their discipline within the context of a technologically important problem, (ii) working as members of an interdisciplinary team that includes scientists from a world leading company in this area (General Electric) collaborating with academics with diverse background and expertise, and (iii) having access to internships at a premier corporate research center (GE-Global Research). As research becomes increasingly global, it is deemed invaluable for students to have experiences in doing research abroad. This program offers such opportunities at collaborating institutions in Europe, Latin America and Pacific Rim countries, including GE-GRC in Bangalore. The program will benefit from the excellent outreach infrastructure of the participating universities, and the proven record of the investigators involving undergraduates and members of underrepresented groups in their research. The fundamental nature of the program, its prospective impact on a technology of critical importance to the US economy, and the educational enrichment experiences available to students are fully consistent with the goals of NSF and its sponsoring programs.TECHNICAL DETAILS: The overarching objective of this program is to develop a fundamental understanding of the dynamics of structure evolution in layered systems subject to the extreme environments typical of gas turbine engines, and how these influence system performance. Establishing the fundamentals governing the physico-chemical phenomena within and between layers will enable the design of improved protection concepts for next generation turbine systems that operate at higher temperature. The information generated will also facilitate validation and refinement of system-level models used for design and durability assessments. The research aims to distil phenomena having crucial impact on a technologically important system by integrating component/layer functionalities with the evolutionary processes that lead to their degradation. Because of the complexity of the system and the scale of the layers, new high-resolution probes occupy a central role. Scientific advances are envisaged within the following five themes. (a) Phase evolution in refractory oxides caused by the decomposition of metastable phases and of clustering in multi-doped systems. (b) Surface diffusion in oxides, including its dependence on dopants, and its effects on the sintering of textured columnar structures. (c) The evolution of stresses and deformations induced by the thermal growth of alumina. (d) The effects of inter-diffusion between layers on phase evolution, on volumetric strains and on stress-inducing transformations; including the behavior of structurally compatible diffusion barriers. (e) The effects of structural evolution on the critical properties, especially the toughness of the various layers and interfaces, the constitutive behavior at high temperature, and the optical and thermal properties of the oxides. Projects are designed to foster collaboration, especially among students and post-docs, and to promote co-advising. Extramural experiences, especially at GE-GRC, allow students to have access to unique facilities and the interaction with industrial scientists contributes to developing an appreciation of how their dissertation research contributes to the overall effort and the progress of the field.FUNDING: This project is co-funded by the Office of International Science and Engineering, the Engineering directorate, and the Ceramics Program within the Mathematical and Physical Sciences directorate.