Defect-Electron Interaction at Ambient Temperature in Metallic Materials

金属材料中环境温度下的缺陷-电子相互作用

• 批准号: 2103928
• 负责人: Md Haque
• 金额: $ 22万
• 依托单位: Pennsylvania State Univ University Park
• 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: 2022-06-15 至 2025-05-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2103928&HistoricalAwards=false
• 关键词: Defect; Electron; Interaction; Ambient; Temperature

Non-technical SummaryHigh temperature has been used to process metallic materials since prehistoric times. The intense heat moves out the otherwise immobile internal defects and thus improves the properties. The same principle is used today. For example, steel processing requires temperatures in excess of 800 C applied for many hours. This research project aims to transform the current state-of-the-art by asking the question, can metals be processed at room temperature? The hypothesis is that, by passing high current - but not allowing the temperature to rise, a purely mechanical force can be generated inside the material. This force can make the defects mobile without raising the temperature and in a timeframe of minutes only. Accordingly, the objective of this research is to understand how the electrons (from current flow) interact with the defects, and how the elimination or rearrangement of defects is different from conventional heat treatment. These experiments are performed inside high magnification microscopes to develop fundamental insights of the proposed process. Accomplishment of this project will give a new alternative to the metallic processing industry, which consumes a big portion of US energy (and carbon) footprint. The new science can also be employed in other systems where current can be passed, like electronics. By bypassing high temperature, this new process may impact the economy of manufacturing industry. The immediate impact is education and training of graduate and undergraduate students, while promoting diversity. The project involves student from middle school to enhance awareness of the carbon economy of manufacturing, and underlying science, to the next generation.Technical SummaryDefect and microstructural control in metals and alloys require very high temperature (comparable to melting point) and long times (from few hours to days). In this project, the PIs propose a non-thermal force to achieve the same effects in minutes. Here, electrical current is passed through the specimen, while controlling its temperature to the ambient. Whenever the electrons collide with defects and grain boundaries, they lose the momentum – generating the ‘electron wind force’ (EWF). The hypothesis is that the EWF dissociates immobile and complex defects species to create very high density of disentangled and mobile dislocations. This allows the EWF to impart high mobility to the defects without raising the temperature. The specific objectives of this project are to (a) provide direct evidence of defect and microstructural control by performing fundamental experiments inside microscopes with near-atomic resolution and (b) investigate the electron-defect interaction to predict the evolution of various defect species (vacancies, partials, dislocations, twins) and correlate that to the microstructural changes. The transformative aspect of this project is the departure from centuries-old heat treatment techniques to the proposed non-thermal process. It explores the atomic to grain level fundamentals of defect-EWF interaction, which remain mostly unknown. The research is integrated with undergraduate education through Senior Capstone design course to train the next generation with emerging manufacturing technology. A student recruitment is through the Penn State Minority/Women in Engineering program. A unique outreach program, Print with Metals, is developed for Middle school students. These activities are complemented by the Manufacturing Day event to draw high and middle school students towards engineering, and specifically next generation manufacturing careers.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.

非技术概述自史前时代以来，高温一直用于加工金属材料。强热去除了原本固定的内部缺陷，从而改善了性能。同样的原则今天也在使用。例如，钢铁加工需要超过800摄氏度的温度，持续数小时。该研究项目旨在通过提出金属可以在室温下加工的问题来改变当前的最先进技术。假设是，通过传递高电流-但不允许温度上升，可以在材料内部产生纯机械力。该力可以使缺陷移动的而不升高温度并且仅在几分钟的时间内。因此，本研究的目的是了解电子（来自电流）如何与缺陷相互作用，以及缺陷的消除或重排与常规热处理有何不同。这些实验在高放大率显微镜内进行，以开发所提出的过程的基本见解。 该项目的完成将为金属加工行业提供新的替代方案，该行业消耗了美国能源（和碳）足迹的很大一部分。新科学也可以用于其他电流可以通过的系统，如电子学。通过绕过高温，这种新工艺可能会影响制造业的经济。直接影响是对研究生和本科生的教育和培训，同时促进多样性。该项目涉及从中学的学生，以提高意识的碳经济的制造业，和基础科学，到下一代。技术摘要金属和合金的缺陷和微观结构控制需要非常高的温度（相当于熔点）和长时间（从几个小时到几天）。在这个项目中，PI提出了一种非热力，以在几分钟内达到相同的效果。在这里，电流通过试样，同时将其温度控制在环境温度。每当电子与缺陷和晶界碰撞时，它们就会失去动量-产生“电子风力”（EWF）。假设是EWF使不移动的和复杂的缺陷物质解离以产生非常高密度的解纠缠和移动的位错。这允许EWF在不升高温度的情况下赋予缺陷高迁移率。该项目的具体目标是：（a）通过在近原子分辨率的显微镜内进行基本实验，提供缺陷和微观结构控制的直接证据;（B）研究电子-缺陷相互作用，预测各种缺陷种类（空位、部分、位错、孪晶）的演变，并将其与微观结构变化相关联。该项目的变革性方面是从几个世纪以来的热处理技术转向拟议的非热处理工艺。它探讨了原子晶粒级的缺陷EWF相互作用的基本原理，这仍然是未知的。该研究通过高级顶点设计课程与本科教育相结合，以培养具有新兴制造技术的下一代。学生招聘是通过宾夕法尼亚州立大学少数民族/妇女在工程计划。一个独特的推广计划，打印与金属，是为中学生开发的。除了这些活动外，还举办了“制造日”活动，旨在吸引高中生投身工程领域，尤其是下一代制造业。该奖项反映了NSF的法定使命，并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，被认为值得支持。