Determining Pathways for Improved Oxidation Resistance in Compositionally Complex Alloys

确定提高成分复杂合金的抗氧化性的途径

基本信息

批准号：
2105364
负责人：
Mark Weaver
金额：
$ 32.45万
依托单位：
University of Alabama Tuscaloosa
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2021
资助国家：
美国
起止时间：
2021-08-01 至 2024-07-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2105364&HistoricalAwards=false
关键词：
Determining Pathways Improved Oxidation Resistance

项目摘要

NON-TECHNICAL SUMMARYMetal alloys are widely used as structural materials in many high temperature applications such as power plants, aircraft engines, and rocket motors. Conventional alloys are typically made of one or two primary alloying elements with addition of other low-concentration alloying elements to improve alloy properties. Recently, high entropy alloys, also known as complex concentrated alloys, have received significant interest due to their novel structures and properties. Unlike conventional alloys, high entropy alloys consist of five or more principal alloying elements in nearly equal concentrations. These concentrated alloys exhibit outstanding physical properties compared to conventional alloys including high-temperature strength, corrosion resistance, and radiation tolerance, though the reasons why are poorly understood to date. This project investigates the fundamental mechanisms of high temperature oxidation in high entropy alloys and establishes the roles of chemistry and microstructure in controlling oxidation behavior. Through this project a diverse group of students and scientists, including women and students from Historically Black Colleges and Universities, will be trained to test, characterize, model and predict the oxidation behavior of high entropy alloys using computational and experimental tools. This project will advance our goals towards developing materials with improved oxidation resistance which will contribute towards more fuel efficient and longer lasting power plants, improved jet and rocket engines, and safer nuclear power plants.TECHNICAL SUMMARYHigh entropy alloys (HEAs) and the related complex concentrated alloys (CCAs) are garnering increased attention from the researchers worldwide searching for alternatives to conventional/legacy materials. Oxidation limits the application of many advanced materials in high temperature environments and there have been very few investigations of the oxidation behavior of high entropy alloys. Most of those studies centered on as-fabricated (e.g., as-cast, as-sintered, etc.) alloys without addressing the influences of microstructural parameters (i.e., grain/phase size, morphology, or distribution). This research will use a coupled experimental and computational approach to establish how oxidation occurs in AlCoCrFeNi HEAs/CCAs and will provide a framework that can be used to design and fabricate HEAs/CCAs exhibiting enhanced oxidation resistance. This research will use CALPHAD based thermodynamic modeling to predict phase equilibria and oxidation products and will use TC-PRISMA complemented with DICTRA to simulate phase precipitation due to oxidation. The simulated microstructures and phases will be validated using cross-correlative analytical electron microscopy and Atom Probe Tomography techniques to quantify solute segregation behavior and the influences of phase distribution and grain boundary character on oxidation. This research will contribute towards the development, improvement and validation of high-quality thermodynamic and kinetic databases and will also provide necessary technical insights to facilitate the development of oxidation resistant HEAs for use in high temperature structural applications. The graduate student budgeted for the project will employ the principles of metallurgical and ceramic engineering, thin film science and materials processing, microstructural characterization, and materials selection. They will benefit from this project by being involved in advanced research on the fabrication, chemical and microstructural characterization, and modeling of reacting materials using state-of-the-art analytical and computational tools.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.

在许多高温应用中，例如发电厂，飞机发动机和火箭电动机等许多高温应用中，非技术摘要合金被广泛用作结构材料。常规合金通常由一个或两个主要合金元件制成，并添加其他低浓度合金元素以改善合金性能。最近，由于其新颖的结构和特性，高熵合金（也称为复合浓缩合金）引起了巨大的兴趣。与常规合金不同，高熵合金由五个或更多的主要合金元素组成，几乎相等。与传统合金（包括高温强度，耐腐蚀性和辐射耐受性）相比，这些浓缩合金具有出色的物理特性，尽管迄今为止对知识较差的原因。该项目研究了高温合金中高温氧化的基本机制，并确定了化学和微观结构在控制氧化行为中的作用。通过这个项目，将对使用计算和实验工具的高熵合金进行测试，表征，建模和预测高熵合金的氧化行为，包括历史悠久的黑人学院和大学的学生和科学家组成的各种各样的学生和科学家。该项目将使我们的目标朝着具有改善的氧化耐药性开发材料发展，这将有助于更加燃油效率，更持久的发电厂，改善的喷气式和火箭发动机以及更安全的核电站。技术简介熵合金（HEAS）和相关的复合型浓缩合金（CCAS）在世界范围内搜索替代材料的研究者会增加注意力的注意力。氧化限制了许多晚期材料在高温环境中的应用，并且很少对高熵合金的氧化行为进行研究。大多数研究都集中在固定的（例如，播，插入的）合金上，而无需解决微观结构参数的影响（即晶粒/相大小，形态或分布）。这项研究将使用一种耦合的实验和计算方法来确定Alcocrfeni Heas/CCA中的氧化是如何发生的，并将提供一个框架，可用于设计和制造具有增强氧化耐药性的HEAS/CCA。这项研究将使用基于Calphad的热力学建模来预测相位平衡和氧化产物，并将使用与DICTRA相辅相成的TC-PRISMA来模拟由于氧化而引起的相沉淀。模拟的显微结构和相将使用交叉反复分析电子显微镜和原子探针断层扫描技术进行验证，以量化溶质分离行为以及相分布和晶界特征对氧化的影响。这项研究将有助于高质量热力学和动力学数据库的开发，改进和验证，还将提供必要的技术见解，以促进耐氧化性HEAS的开发，用于高温结构应用。该项目预算的研究生将采用冶金和陶瓷工程，薄膜科学和材料处理，微观结构表征和材料选择的原则。他们将通过使用最先进的分析和计算工具进行制造，化学和微观结构表征的高级研究，以及对反应材料进行建模。该奖项反映了NSF的法定任务，并被认为是值得通过基金会的知识分子功绩和更广泛的审查标准来对反应材料进行建模。