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.

多主元素合金，也称为高熵合金（HEAs），是一类新兴的金属材料，其通常由五种或更多种具有相似浓度的合金元素组成。由于HEAs与传统合金相比具有上级机械性能和化学稳定性，因此作为用于苛刻条件下的潜在结构材料已经引起了相当大的兴趣。尽管HEAs拥有所有的承诺，但对它们在恶劣环境下同时发生机械冲击和化学反应时的表面结构和性能知之甚少。弗吉尼亚理工大学和亚拉巴马大学之间的这项合作研究旨在科学地了解HEAs表面在含氯化物水溶液（例如海水）中同时磨损和生锈（即摩擦腐蚀）后的结构和形成机制。通过结合先进的表面表征工具和多尺度计算机模拟，将建立HEAs的表面缺陷，变形和摩擦腐蚀敏感性之间的联系。该项目将导致设计具有高耐摩擦腐蚀性的金属，用于在恶劣条件下需要高耐磨性和防锈性的关键应用。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方面的多样化培训，以及协作团队经验。它还将积极影响一些教育和推广活动，特别是通过在弗吉尼亚理工大学和亚拉巴马大学的研究机会参与代表性不足的群体。技术摘要我们目前的理解HEAs的摩擦腐蚀机制主要是挑战缺乏理解的选择性溶解/氧化的主要元素，以及新的变形物理在/下的表面。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，特别是对于依赖于薄但保护性的表面氧化层（即钝化层）的含Cr HEA，用于在空气和水中的腐蚀保护。该项目将结合联合收割机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在表面形成远离平衡的微观结构和成分，以及协同作用于整体再钝化动力学和摩擦腐蚀速率的表面电化学和机械的影响。具体而言，PI将（1）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）阐明摩擦腐蚀表面结构的化学、组成和缺陷特征及其形成机制，（3）使用原子模拟了解磨损诱导的缺陷产生和微观结构演变，以及（4）开发实验验证的，摩擦腐蚀的预测模型，采用多物理场模拟，结合限速腐蚀和再钝化步骤。集成的实验和计算方法具有很大的潜力，以减少材料的创建和部署周期，以在比传统已知的更大的设计空间内制造耐摩擦腐蚀合金。弗吉尼亚理工大学和亚拉巴马大学将为本科生，特别是女性（两个PI都是榜样）和代表性不足的少数民族创造研究机会和导师计划。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NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

项目成果

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

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