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

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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.