Accelerated discovery of nanotwinned alloy systems

第1部分。寻找和开发新的更强、更持久的金属材料对于从空间探索到生物植入物的应用具有重要意义。具有纳米级特征的金属，如晶粒尺寸和工程晶界，提供了前所未有的控制，以改善材料的行为。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。纳米孪晶结构可以提高材料的强度、延展性、导电性、热稳定性和耐腐蚀性。在传统的研究方法中，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，新的能力被开发出来，允许同时研究数百种成分，从而将纳米孪晶的发展概率与材料成分联系起来。这种创新的方法可以更快、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，从而将教学和研究无缝结合。与当地一所K-5学校的外展合作为我们最年轻的未来科学家提供了积极的接触和指导。第2部分。技术概述：高度纳米孪晶（NT）显微结构是由合成过程中形成的生长孪晶组成的，它提供了晶界控制和非均质微观结构，可以提高材料的各种性能，如强度、延展性、导电性、热稳定性和耐腐蚀性。然而，由于缺乏与孪晶生长直接相关的材料固有特性——层错能（SFE）的基本数据，进一步理解和有意实施NT微观结构受到了阻碍。该提案旨在通过实施高通量磁控溅射和组合表征以及将孪晶形成与成分联系起来的属性映射来克服为每种所需成分寻找SFE的艰巨任务。通过开发一种可应用于任何合金系统的实验方法，本工作的重点是建立材料库，以连接成分，NT微结构和机械材料性能，这将大大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推广计划，目标是在各个层面建立更多样化的劳动力和可持续的STEM管道。该奖项反映了美国国家科学基金会的法定使命，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。

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.