Accelerated discovery of nanotwinned alloy systems

第一部分非技术总结新的更坚固耐用的金属材料的研究和开发对于从空间探索到生物植入的各种应用具有非常重要的意义。具有纳米级特征的金属，如颗粒尺寸和工程晶界，为改善材料的行为提供了前所未有的控制。纳米孪晶是一种纳米级的边界，可以在加工、变形或热处理过程中引入金属中。纳米孪晶组织可以提高特定材料的强度、延展性、导电性、热稳定性和耐腐蚀性。通过传统的研究方法，了解哪些材料和成分可以在加工过程中形成纳米孪晶是一项非常耗时的任务。在这项提议中，开发了新的能力，允许一次研究数百种成分，将发展成纳米双胞胎的可能性与材料成分联系起来。这一创新方法允许更快、更便宜、更有效地发现和部署新材料。该项目的数据被用于大学生机器学习的计算课堂，从而实现了教学和研究的无缝结合。与当地K-5学校的外展合作为我们未来最年轻的科学家提供了积极的接触和指导。第二部分技术总结由合成过程中形成的生长孪晶组成的高度纳米孪晶(NT)微结构提供了晶界控制和异质微结构，可以改善各种性能，如强度、延展性、导电性、热稳定性和耐腐蚀性。然而，由于缺乏关于层错能(SFE)的基本数据，对NT微观结构的进一步理解和刻意实施一直受到阻碍，SFE是一种与孪晶生长直接相关的内在材料特性。这一建议旨在通过实施高通量磁控溅射和将孪晶形成与组合物联系起来的组合表征和属性图来克服为每一种所需组合物寻找超临界流体效应的艰巨任务。这项工作的重点是建立材料库，将成分、NT微观结构和机械材料性能联系起来，通过开发一种可应用于任何合金系统的实验方法，极大地扩展和加快材料设计。该项目的更广泛影响包括参与针对K-12、本科生和研究生的教育和外展计划，目标是在每个级别建立更多样化的劳动力和可持续的STEM管道。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。

Part 1. NON-TECHNICAL SUMMARYThe search and development of new stronger and long-lasting metallic materials are of high importance for applications ranging from space exploration to biological implants. Metals with nanoscale features such as grain sizes and engineered grain boundaries provide unprecedented control to improve a material’s behavior. A nanotwin is a type of boundary at the nanoscale that can be introduced in a metal during processing, deformation or by a heat treatment. Nanotwin microstructures can enhance the strength, ductility, conductivity, thermal stability, and corrosion resistance of a given material. Understanding which materials and compositions can form nanotwins during processing is a very time intensive task when performed by traditional research methods. In this proposal, new capabilities are developed to allow the study of hundreds of compositions at once to link the probability of developing nanotwins with material composition. This innovative approach allows for faster, cheaper, and more effective discovery and deployment cycles for new materials. Data from this project are used in computational classes for machine learning for university students, thus seamlessly combining teaching and research. Outreach collaborations with a local K-5 school provide positive exposure and mentoring to our youngest future scientists. Part 2. TECHNICAL SUMMARYHighly nanotwinned (NT) microstructures, which are composed of growth twins formed during the synthesis process, provide grain boundary control and a heterogeneous microstructure which can improve a variety of properties such as strength, ductility, conductivity, thermal stability, and corrosion resistance. However, further understanding and the deliberate implementation of NT microstructures has been hindered by a lack of fundamental data on stacking fault energy (SFE), an intrinsic material property directly correlated to twin growth. This proposal aims to overcome the prohibitively large task of finding a SFE for every desired composition by implementing high-throughput magnetron sputtering and combinatorial characterization and property mapping that links twin formation with composition. This work focuses on building materials libraries to connect compositions, NT microstructures, and mechanical material properties which would greatly expand and expedite materials design, by developing an experimental methodology that can be applied to any alloy system. The broader impacts for this project include participation in education and outreach programs targeting K-12, undergraduate, and graduate students with the goals of building a more diverse workforce and a sustainable STEM pipeline at every level.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.