Understanding Intrinsic Ductility in Metallic Glasses

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TECHNICAL SUMMARYThis award supports computational and theoretical research and education to advance understanding of the intrinsic ductility of metallic glasses. The conditions and manner in which materials fail are of fundamental concerns to both engineers and scientists. Recently an empirical relation has been found between the Poisson's ratio and the fracture energy in amorphous solids, including metallic glasses and oxide glasses. However, there is little theoretical understanding for such a convenient and intriguing correlation between near-equilibrium elasticity and far-from-equilibrium failure. The PI will use molecular dynamics simulation coupled with potential-tuning scheme to investigate the intrinsic ductility of metallic glasses, as a prototypical amorphous solid. Such strategy will enable the exploration of amorphous solids unavailable in experiments by prescribing atomic interactions. Both the Poisson's ratio and the fracture energy will be studied in terms of the atomic bonding and packing. The knowledge of how structure determines intrinsic ductility is crucial to toughening metallic glasses and even oxide glasses. The computational platform developed in this project can be used to conduct dynamic fracture and fatigue testings, and to study fracture toughness of thin films, porous materials and composite materials. Insights gained here will also provide important clues on other empirical relations linking the Poisson's ratio to densification, fragility and glass-transition.The PI will reach out to high school students interested in science and engineering through the New Visions: Math, Engineering, Technology & Science program in collaboration with Rensselaer Polytechnic Institute. Planned activities include half-day mini-lectures on computational materials science, complemented with interactive demonstrations. The PI will also reach out to the computational research community by continuing developing open-source visualization software SimRePlay.NON-TECHNICAL SUMMARYThis award supports computational and theoretical research and education to understand how amorphous solid materials fail. The touch screens of smart phones, made of oxide glasses, are brittle as they shatter upon impact, while glasses constituted with metal atoms, termed metallic glasses, can be as tough as steels. The PI will use advanced computer simulation techniques to model the fracture of various amorphous solids. The insights gained from computational work at the atomic level will help understand and predict the failure mode of amorphous solids, and provide important clues of how to make tough glasses.The PI will reach out to high school students interested in science and engineering through the New Visions: Math, Engineering, Technology & Science program in collaboration with Rensselaer Polytechnic Institute. Planned activities include half-day mini-lectures on computational materials science, complemented with interactive demonstrations. The PI will also reach out to the computational research community by continuing developing open-source visualization software SimRePlay.