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Lijie He1 Haomin Liu1 Niaz Abdolrahim1

1, University of Rochester, Brighton, New York, United States

Nanoporous (NP) metallic materials exhibit microscale plasticity, but macroscopically fail in a relatively brittle-like manner. In this study, Molecular dynamics (MD) simulations are employed to investigate governing deformation mechanisms responsible for ductile behavior of the constituent ligaments of NP structure (nanowires) how it can be related to their triple nodal network. Shear strain tensor analysis is used to differentiate deformation mechanisms accommodating strain among nanowires and triple nodes during stretching. In addition, a computational analysis method is used to quantify plastic and elastic deformation. In general, dislocation activity accommodates 10% to 20% of total plastic deformation while most of the plastic strain generates within bulk and surface atoms. We also studied the deformation behaviors of triple nodes and found out that yield strength of triple node structure is quite close to the strength of NP structure. This further means that the brittle behavior of the NP system can be represented as a function of nodal deformation rather than ductile deformation of only single ligaments. Our preliminary results also suggest that core-shell ligaments can increase both ductility and strength of the NP structure due to the increased activity of twins while nucleation of partials are prominent in monolithic ligaments with no shell layer.

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