2D Grain Boundary Phases: Establishing an Electronic Basis for Engineering Superior Copper Alloy Behavior

非技术总结：金属和合金（混合物），如青铜，已经被人类使用了几千年之前，物质的原子性质是已知的。即使在今天，原子如何相互作用的细节也只知道金属的几种组合，因为在原子水平上研究材料的工具直到最近才出现。这些细节变得越来越重要，因为现代技术的进步要求更小、更轻、更紧凑的设计和更高的功能。这个项目将探索为什么添加某些金属会使铜更柔韧，而其他金属会使铜更脆（或更强/更弱，或更导电性更差）。这种行为的起源可以追溯到原子和它们的电子在称为晶界的内部缺陷处的相互作用，在那里原子不完美地聚集在一起。这些边界存在于所有金属中，并极大地影响金属部件的性能，从计算机芯片中的电线到飞机上的座椅托架。了解这些相互作用将使工程师能够首次从原子水平向上设计合金，使他们能够定制合金的特性，以减少制造中使用的功率，延长金属部件的使用寿命，或者在不影响性能的情况下创建复杂的设计。这项工作的成果将由学生在国家和国际技术会议上与科学界和工业界分享，这些学生毕业后将成为受过高等教育和实际训练的劳动力成员。参与该项目的学生还将通过纽约州立大学保利分校现有的几个项目获得拓展和指导的机会，包括中学教师的继续教育，高中生的暑期科学营，以及当地公共图书馆分馆的普通科学系列研讨会。这位教授和她的团队致力于消除技术的神秘性，让所有人都能接触到科学（和科学家）。技术概述：晶界强烈影响多晶金属的一系列性能和行为；在纳米结构材料中，这种效应可能更加显著，因为参与这些边界的原子数量占样品中总原子的相当一部分。因此，可观察的性质通常是由界面而不是材料的体积性质决定的。溶质在部分或全部这些界面上的偏析可以通过与周围基体的电子相互作用改变边界的能量、迁移率、结构和内聚力。这些相互作用的性质将使用分析透射电子显微镜，电子能量损失光谱和密度泛函理论的组合进行检查。这些结果将用于阐明晶界原子和电子结构之间的相关性以及所观察到的铜合金的机电性能，从而使未来的材料设计成为可能。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。

Non-technical summary: Metals and alloys (blends) such as bronze have been used by mankind for millennia before the atomic nature of matter was known. Even today, the details of how atoms interact are known only for a few combinations of metals, because the tools for studying materials at the atomic level have only recently become available. Those details have become increasingly important as modern technological advances demand smaller, lighter, and more compact designs with increased capabilities. This project will explore why adding certain metals make copper more flexible while others make it more brittle, (or more/less strong, or more/less conductive). The origin of this behavior can be traced to the interaction of the atoms and their electrons at internal defects called grain boundaries, where the atoms are packed together imperfectly. These boundaries are found throughout all metals, and greatly impact the behavior of metal parts, from wires in computer chips to seat brackets in airplanes. Understanding these interactions will allow engineers to design alloys from the atom level upward for the first time, enabling them to tailor properties of the alloys to reduce the power used in manufacturing, to prolong the service life of metal parts, or to create complex designs without compromising performance. The results of this work will be shared with the scientific and industrial communities at national and international technical conferences by students who, when they graduate, will become highly educated and practically trained members of the workforce. Participating in this project will also expose students to outreach and mentoring opportunities through several existing programs at SUNY Poly, including the continuing education of secondary school teachers, summer science camps for high school students, and a general science seminar series at a local branch of the public library. The professor and her team are committed to these efforts to de-mystify technology and make science (and scientists) accessible to all. Technical summary: Grain boundaries strongly impact a range of properties and behavior of polycrystalline metals; in nanostructured materials this effect can be even more dramatic because the number of atoms participating in those boundaries constitutes an appreciable fraction of the total atoms in the sample. As a result, observable properties are often dominated by interface, not bulk, material properties. Solute segregating to some or all of these interfaces can change the energy, mobility, structure and cohesion of boundaries through electronic interactions with the surrounding matrix. The nature of these interactions will be examined using a combination of analytical transmission electron microscopy, electron energy loss spectroscopy, and density functional theory. These results will be used to elucidate the correlations between the atomic and electronic structures at grain boundaries and observed electro-mechanical properties of select copper alloys, to enable future materials-by-design.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.