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: 2333517
• 负责人: Lin Li
• 金额: $ 25.71万
• 依托单位: Arizona State University
• 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: 2023-07-15 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2333517&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.

非技术摘要多主元素合金，也称为高熵合金 (HEA)，是一类新兴的金属材料，通常由五种或更多浓度相似的合金元素组成，HEA 作为潜在的结构材料引起了极大的兴趣。与传统合金相比，由于其优异的机械性能和化学稳定性，可在恶劣条件下使用尽管 HEA 具有许多前景，但人们对其在恶劣环境下同时发生机械冲击和反应时的表面结构和性能知之甚少。弗吉尼亚理工大学和阿拉巴马大学之间的研究旨在通过结合先进的表面技术，对含氯水溶液（例如海水）中同时磨损和生锈（即摩擦腐蚀）后的 HEA 表面结构和形成机制进行科学理解。通过表征工具和多尺度计算机模拟，将建立 HEA 的表面缺陷、变形和摩擦腐蚀敏感性之间的联系，该项目将导致金属的设计。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以及协作团队合作方面的多样化培训。它还将对多项教育和推广活动产生积极影响，特别是通过弗吉尼亚理工大学和阿拉巴马大学的研究机会让代表性不足的群体参与进来。技术摘要我们目前对 HEA 摩擦腐蚀机制的理解主要受到缺乏了解的挑战。主要元素的选择性溶解/氧化，以及表面/表面以下的新变形物理，机械和化学侵蚀之间的协同作用极大地改变了材料的表面状况和腐蚀敏感性，特别是对于依赖于腐蚀的含铬 HEA。用于空气和水中腐蚀防护的薄而保护性的表面氧化层（即钝化层）该项目将结合先进的表面表征和多尺度模拟，以揭示摩擦滑动引起的去钝化如何导致。表面远离平衡微观结构和成分的形成，以及表面电化学和机制对整体再钝化动力学和摩擦腐蚀速率的协同作用的影响，具体而言，PI 将 (1) 决定合金浓度和晶粒尺寸。影响磨损、腐蚀及其协同作用，(2) 阐明摩擦腐蚀表面结构的化学、成分和缺陷特征及其形成机制，(3) 理解(4) 使用多物理场模拟开发经过实验验证的摩擦腐蚀预测模型，其中包含限速腐蚀和再钝化步骤。集成的实验和计算方法具有减少磨损的巨大潜力。弗吉尼亚理工大学和阿拉巴马大学将为本科生，特别是女性学生，提供比传统已知的更大设计空间的材料创造和部署周期，以制造耐摩擦腐蚀合金。 （以两位 PI 为榜样）和代表性不足的少数群体 此外，拟议的外展活动将对当地 K-12 学生和广大互联网受众产生积极影响，以提高他们对 STEM 领域的兴趣并增强他们的知识。该奖项反映了这一点。通过使用基金会的智力价值和更广泛的影响审查标准进行评估，NSF 的法定使命被认为值得支持。