Role of Diffusion-Induced Grain Boundary Migration in Alloy Oxidation

扩散引起的晶界迁移在合金氧化中的作用

• 批准号: 2236887
• 负责人: Emmanuelle Marquis
• 金额: $ 39.73万
• 依托单位: Regents of the University of Michigan - Ann Arbor
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2236887&HistoricalAwards=false
• 关键词: Role; Diffusion; Induced; Grain; Boundary

NON-TECHNICAL SUMMARYOxidation resistance remains a critical requirement for materials applications at medium to hightemperatures in many key sectors such as energy, transportation, and aerospace. Decades of studies have generated significant knowledge about how to improve the oxidation resistance of structural materials, with strategies including the use of alloying elements, coatings, and surface treatments. However, many of the mechanisms behind these strategies remain elusive limiting our ability to design better performing alloys. In this context, the project addresses the impact of deformation and small grain sizes on the oxidation response of selected structural alloys. The work specifically focuses on elucidating the key role of diffusion along moving grain boundaries supplying elements to the alloy surface to form an oxide layer. This ubiquitous mechanism has been largely ignored and therefore unexplored in the context of alloy oxidation; yet it can explain the impacts of surface deformation and small grain sizes on the oxidation behavior of alloy systems.This program contributes to the general scientific understanding of diffusion along moving grain boundaries as a ubiquitous mechanism in crystalline materials under diffusive conditions and increases our mechanistic understanding of materials under extreme environments with impact on the development of new alloys and microstructures, particularly in the context of advanced manufacturing processes. Because of its focus on materials under extreme environments and specifically high temperature oxidation, the proposed research impacts key areas of industrial and national importance, including transportation, energy, and aerospace. In addition to its scientific and technological impacts, the program also contributes to the recruitment, retention, and training in advanced research methods and techniques of a diverse student body and workforce through its research activities. The project also includes activities and practices focusing on increasing diversity, equity, inclusion, and accessibility awareness in the classroom, laboratories, and campus wide.TECHNICAL SUMMARYOxidation resistance remains a critical requirement for applications at medium to high temperatures in many key sectors (energy, transportation, aerospace). While avenues to improve the oxidation resistance of structural materials, i.e., alloying, coating, and surface treatments, are commonly used, many of the mechanisms behind these strategies remain elusive limiting our ability to design better performing alloys. The project addresses the hypothesis that diffusion-induced grain boundary migration (DIGM) is ubiquitous in alloy oxidation and uniquely explains the impacts of surface deformation and grain refinement on the oxidation behavior of alloy systems. To support this hypothesis, this project uses a series of increasingly complex alloys, from model Ni alloys to multi principal element alloys for which diffusion kinetics have been the object of debate. The program quantifies DIGM during alloy oxidation, generating observations, experimental data, and analyses necessary to increase our understanding of solute transport and phase transformation during DIGM with implications for not only oxidation modeling and mitigation but also for any conventional and complex concentrated alloy under diffusive conditions at intermediate temperatures where DIGM can occur. The approach combines systematic series of experiments using state-of-the-art characterization techniques tying micron scale observations to atomistic mechanisms, establishing the knowledge base for future modeling and computational approaches within the Materials Genome Initiative.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.

非技术总结氧化耐药性仍然是在许多关键部门（例如能源，运输和航空航天）中的材料应用到中等水平的材料应用的关键要求。数十年的研究已经产生了有关如何改善结构材料氧化抗性的重要知识，并采用了包括使用合金元素，涂料和表面处理的策略。但是，这些策略背后的许多机制仍然难以捉摸，从而限制了我们设计更好的合金的能力。在这种情况下，该项目解决了变形和小晶粒尺寸对选定结构合金氧化响应的影响。这项工作专门侧重于阐明沿运动晶界扩散的关键作用，向合金表面提供元素以形成氧化物层。这种无处不在的机制在很大程度上被忽略了，因此在合金氧化的背景下未开发。然而，它可以解释表面变形和小谷物大小对合金系统的氧化行为的影响。该程序有助于对沿移动晶界扩散的一般科学理解，因为在弥散条件下，在晶体材料中的一种无处不在的机制有助于我们在材料中对材料的机械理解的影响，并影响了我们在新的合金和机构中的发展，尤其是在材料中的机械理解，尤其是在新的合并构造中，尤其是在新的材料中的开发。由于其专注于极端环境，特别是高温氧化的材料，因此提出的研究影响了工业和国家重要性的关键领域，包括运输，能源和航空航天。除了其科学和技术影响外，该计划还通过其研究活动进行了多样化的学生团体和劳动力的高级研究方法和技术的招聘，保留和培训。该项目还包括着重于增加课堂，实验室和校园的多样性，公平，包容性和可及性的活动和实践。技术摘要氧化阻力仍然是许多关键部门（能源，运输，航空航天）中等高温的应用程序的至关重要的要求。尽管通常使用了改善结构材料（即合金，涂料和表面处理）的氧化抗性的途径，但这些策略背后的许多机制仍然难以限制，从而限制了我们设计更好地性能的能力。该项目解决了以下假设：扩散引起的晶界迁移（DIGM）在合金氧化中无处不在，并且独特地解释了表面变形和细化对合金系统氧化行为的影响。为了支持这一假设，该项目使用了一系列日益复杂的合金，从模型NI合金到多主元素合金，扩散动力学一直是辩论的对象。该程序在合金氧化过程中量化了DIGM，产生观察结果，实验数据和分析，以增强我们对DIGM期间溶质传输和相位转化的理解，这不仅对氧化建模和缓解措施，而且对任何常规且复杂的合金在扩散条件下在中等温度下发生的任何常规且复杂的合金都有影响。该方法使用最先进的表征技术将微米量表观测与原子机制相关联，为材料基因组计划中的未来建模和计算方法建立知识基础，结合了系统的实验系列。该奖项反映了NSF的立法任务，并被认为是通过基金会的智力评估和广泛的Cragitia Croctiation和Sparritia的评估来评估。