ERI: Mechanical Behavior of Dualphase Complex Concentrated Alloys at Elevated Temperatures

ERI：双相复杂浓缩合金在高温下的机械行为

• 批准号: 2138674
• 负责人: Xuejun Fan
• 金额: $ 17.75万
• 依托单位: Lamar University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-02-01 至 2025-01-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2138674&HistoricalAwards=false
• 关键词: ERI; Mechanical; Behavior; Dualphase; Complex

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).This Engineering Research Initiative (ERI) project is to study a special type of alloy called complex concentrated alloys (CCAs). CCAs are materials recently found to have superior mechanical properties. Materials that have high strength at high temperature are highly desirable for many engineering applications. CCAs consist of multiple principal elements and include high-entropy alloys, which contain five or more principal elements. CCAs have been researched as potential structural alloys for high temperature applications, such as heat exchangers, gas turbines, and nuclear reactors. Generally, single-phase face-centered cubic CCAs have low strength at high temperatures. Meanwhile, single-phase body-centered cubic CCAs are brittle at room temperature. Dualphase (face-centered cubic and body-centered cubic) CCAs capture the best of the features. They can exhibit both good ductility at room temperature and high strength at high temperatures. However, the current understanding of the mechanical behavior in dualphase CCAs is limited. This project aims to investigate mechanical behaviors and find the best ways to improve the strengths of dualphase CCAs at various temperatures. The knowledge learned from this project could lead to the design of dualphase CCAs for high temperature applications. The multi-disciplinary research will provide graduate students with diverse training in various engineering fields. This project will also positively impact research opportunities of underrepresented groups and engineering education.The objective of this project is to fundamentally understand how interface, microstructure, and chemistry affect the strength and deformability of dualphase CCAs from room temperature to high temperatures. Specifically, the PI will (1) investigate the interplay between temperature-dependent barrier strength of face-centered cubic and body-centered cubic CCAs; (2) reveal the role of interface on dislocation transmission and plasticity transfer between phases; (3) elucidate the effects of dislocation activities on fracture resistance of dualphase CCAs. To address these scientific questions, this project will employ site-specific nanoindentation to probe the mechanical behavior and deformation mechanisms in dualphase CCAs at various temperatures and perform detailed surface morphology and microstructure characterization through high resolution scanning probe microscopy and electron microscopy. The results of this project can provide knowledge to alleviate the brittle failure of body-centered cubic CCAs at room temperature through interfaces and enhance the high temperature strength of dualphase CCAs.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.

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公法117-2)。这个工程研究计划(ERI)项目是为了研究一种特殊类型的合金，称为复杂的浓缩合金(CCA)。CCAS是最近发现的具有优异机械性能的材料。高温下具有高强度的材料在许多工程应用中具有非常高的要求。CCAS由多个主元素组成，包括含有五个或五个以上主元素的高熵合金。CCAS已被作为潜在的高温结构合金进行研究，如换热器、燃气轮机和核反应堆。一般情况下，单相面心立方CCA的高温强度较低。同时，单相体心立方CCA在室温下呈脆性。双阶段(以脸为中心的立方体和以身体为中心的立方体)CCA捕捉到了最好的特征。它们在室温下表现出良好的延展性，在高温下表现出高强度。然而，目前对双相CCA力学行为的理解是有限的。本项目旨在研究两相混凝土在不同温度下的力学行为，并找到提高其强度的最佳方法。从这个项目中学到的知识可以指导高温应用的双相CCA的设计。多学科研究将为研究生提供不同工程领域的多样化培训。该项目还将对未被充分代表的群体的研究机会和工程教育产生积极的影响。该项目的目标是从根本上了解界面、微观结构和化学成分如何影响从室温到高温的双相CCA的强度和变形能力。具体地说，PI将(1)研究面心立方和体心立方CCA势垒强度随温度变化的相互作用；(2)揭示界面对位错传递和相间塑性传递的作用；(3)阐明位错活动对双相CCA断裂抗力的影响。为了解决这些科学问题，本项目将使用特定位置的纳米压痕来探索不同温度下双相CCA的力学行为和变形机制，并通过高分辨率扫描探针显微镜和电子显微镜进行详细的表面形貌和微结构表征。该项目的成果可以提供知识，以减轻体心立方CCA在室温下通过界面的脆性破坏，并提高双相CCA的高温强度。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。