Collaborative Research: Far-from-equilibrium surfaces of high entropy alloys: interplay between frictional sliding and corrosion damage

合作研究：高熵合金的非平衡表面：摩擦滑动与腐蚀损伤之间的相互作用

• 批准号: 2104655
• 负责人: Wenjun Cai
• 金额: $ 42.05万
• 依托单位: Virginia Polytechnic Institute and State University
• 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 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2104655&HistoricalAwards=false
• 关键词: Collaborative; Research; Far; equilibrium; surfaces

Non-Technical SummaryMulti-principal-element alloys, also known as high entropy alloys (HEAs), are an emerging class of metallic materials which often consist of five or more alloying elements with similar concentration. HEAs have generated considerable interest as potential structural materials for use under harsh conditions due to their superior mechanical properties and chemical stability compared to traditional alloys. Despite all of the promise that HEAs hold, little is known about their surface structure and properties upon simultaneous mechanical impacts and chemical reactions under harsh environments. This collaborative research between Virginia Tech and the University of Alabama aims to develop a scientific understanding of the structure and formation mechanism of the surface of HEAs after simultaneous wear and rusting (i.e. tribocorrosion) in chloride-containing aqueous solution (e.g. seawater). By combining advanced surface characterization tools and multi-scale computer simulations, the link between surface defects, deformation, and tribocorrosion susceptibility of HEAs will be established. This project will lead to the design of metals with high tribocorrosion resistance for critical applications which require high wear and rust resistance under harsh conditions. The highly cross-disciplinary research activities will provide graduate students with diverse training in materials science, tribology, corrosion, and computational materials science, as well as the collaborative teamwork experience. It will also positively impact several education and outreach initiatives, especially the involvement of underrepresented groups via research opportunities at Virginia Tech and the University of Alabama.Technical SummaryOur current understanding of the tribocorrosion mechanisms of HEAs is mainly challenged by a lack of understanding of the selective dissolution/oxidation of principal elements, as well as the new deformation physics at/below the surface. The synergy between mechanical and chemical attack drastically alters the materials’ surface condition and corrosion susceptibility, especially for Cr-containing HEAs that rely on a thin yet protective surface oxide layer (i.e. passive layer) for corrosion protection in air and water. This project will combine advanced surface characterization and multi-scale simulations to reveal how frictional sliding-induced depassivation leads to the formation of far-from-equilibrium microstructure and composition at the surface, and the influence of the surface electrochemistry and mechancis that act synergistically on the overall repassivation kinetics and tribocorrosion rate. Specifically, the PIs will (1) determine how alloy concentration and grain size affect wear, corrosion, and their synergy, (2) elucidate the chemistry, composition, and defect characteristics of the tribocorroded surface structure and its formation mechanism, (3) understand wear-induced defect generation and microstructure evolution using atomistic simulations, and (4) develop an experimentally validated, predictive model for tribocorrosion using multiphysics simulations that incorporate rate-limiting corrosion and repassivation steps. The integrated experimental and computational approach has great potential to reduce the materials creation and deployment cycle to fabricate tribocorrosion-resistant alloys over a larger design space than traditionally known. Research opportunities and mentorship programs will be created at Virginia Tech and the University of Alabama for undergraduate students, especially for women (with both PIs serving as role models) and under-represented minorities. In addition, the proposed outreach activities will positively impact local K-12 students and the broad internet audience to promote their interest and enhance their knowledge in STEM fields.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.

非技术总结多元元素合金，也称为高熵合金（HEAS），是一类新兴的金属材料，通常由五个或更多的合金元素组成，其浓度相似。与传统合金相比，由于其优异的机械性能和化学稳定性，HEAS引起了人们的考虑，作为在有害条件下使用的潜在结构材料。尽管有所有希望HEAS保持的承诺，但在Harmsh环境下同时的机械影响和化学反应，它们的表面结构和特性知之甚少。弗吉尼亚理工大学与阿拉巴马大学之间的这项合作研究旨在在同时磨损和生锈（即互动）中对Heas表面的结构和形成机制进行科学理解（例如，互动）。通过结合高级表面特征工具和多尺度计算机模拟，将建立表面缺陷，变形和HEAS的互动敏感性之间的联系。该项目将导致对重要应用具有高摩擦腐蚀性的金属设计，这些应用需要在Harmsh条件下进行高磨损和抗锈蚀。高度跨学科的研究活动将为研究生提供材料科学，摩擦学，腐蚀和计算材料科学的潜水员培训，以及协作团队合作经验。它还将对几项教育和外展计划产生积极影响，尤其是通过弗吉尼亚理工大学和阿拉巴马大学的研究机会参与不足的团体。机械和化学攻击之间的协同作用会大大改变材料的表面状况和腐蚀易感性，尤其是对于依赖于薄薄但受保护的表面氧化物层（即被动层）以在空气和水中保护腐蚀的HEAS。该项目将结合先进的表面表征和多尺度模拟，以揭示摩擦滑动诱导的深度活化如何导致表面上远程平衡微观结构和组成的形成，以及表面电化学和机制的影响，从而在整体重新启动的Kinetics和Trorbocorosorsics率上具有协同作用。具体而言，PIS（1）将确定合金浓度和晶粒尺寸如何影响磨损，腐蚀及其协同作用，（2）阐明锥形交流表面结构及其形成机制的化学，组成和缺陷特征及其形成机制，（3）理解使用ATOMIC的型号，（4）使用ATOMIC模拟，（4）了解疲劳的产生和（4）实验，（4）结合了限速腐蚀和重新激活步骤的仿真。综合实验和计算方法具有减少材料创建和部署周期的巨大潜力，可以在更大的设计空间上制造抗落下抗腐蚀性合金。弗吉尼亚理工大学和阿拉巴马大学的本科生，尤其是女性（PI都用作榜样）和代表性不足的少数群体，将在弗吉尼亚理工大学和阿拉巴马大学创建研究机会和心理计划。此外，拟议的外展活动将对当地的K-12学生和广泛的互联网受众产生积极影响，以促进他们的兴趣并增强他们在STEM领域的知识。该奖项反映了NSF的法定任务，并通过使用该基金会的知识分子和更广泛的影响来评估NSF的法定任务。

项目成果

Understanding Tribocorrosion of Aluminum at the Crystal Level

了解铝在晶体水平上的摩擦腐蚀

• DOI: 10.1016/j.actamat.2022.118639
• 发表时间: 2023
• 期刊: Acta Materialia
• 影响因子: 9.4
• 作者: Wang, Kaiwen;Zhang, Zhengyu;Dandu, Raja Shekar;Cai, Wenjun
• 通讯作者: Cai, Wenjun

Computational design of non-equiatomic CoCrFeNi alloys towards optimized mechanical and surface properties

• DOI: 10.1557/s43578-022-00695-y
• 发表时间: 2022-08
• 期刊: Journal of Materials Research
• 影响因子: 2.7
• 作者: Zhengyu Zhang;Yi Yao;Liping Liu;Tianyou Mou;H. Xin;Lin Li;W. Cai