Connecting Nanoscale Structure and Plasticity in Bulk Metallic Glasses

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The research objective of this award is to connect structure to plastic deformation in bulk metallic glasses (BMGs). Experiments with fluctuation electron microscopy (FEM) will be used to measure nanoscale medium-range order in BMGs. The FEM data will be combined with an empirical interatomic potential in a hybrid Reverse Monte Carlo structural refinement, producing models with realistic short- andmedium-range structure. Research on Pd-Si BMGs will provide an essential test of the generality of a recently proposed structural modelfor Zr-Cu-Al BMGs that consists of nanometer-regions with crystal-like and icosahedral-like internal structure. If crystal-like nanometer scale regions are a general feature of BMG structure, it could have significant impact on models of their plastic flow.If successful, this research will lay the fundamental scientific groundwork for expanded applications of BMG alloys, by eventually assisting design of new alloys with desired mechanical and glass-forming characteristics through detailed understanding of their structure and its connection to plasticity. The research team will involve undergraduate and graduate students, especially from under-represented groups, and will engage the general public and K-12 students in the excitement and outcomes of the research.