A pinboard by
Haomin Liu

Research assistance, University of Rochester


Structurally, nanoporous (NP) system can be regarded as a network of interconnected nanowires as its constituting ligaments. My research is investigating the mechanical behaviors of single-crystalline Cu nanowires aligned in the <001>, <110> and <111> crystallographic directions under tensile loading and their triple junction network using molecular dynamics (MD) simulations. Shear strain tensor analysis is used to differentiate deformation mechanisms accommodating strain among nanowires and capture the necking point during stretching. In addition, a computational analysis method is used to quantify plastic and elastic deformation. The nanowires in different crystallographic orientations behave differently in elongation. Nanowire in the <110> orientation shows enhanced ductility compared to the <001> and <111> directions because of the extended twining activity while dislocation glides lead to necking in the other two nanowires. In general, dislocation activity accommodate 10% to 20% plastic deformation after yielding while most of the plastic strain generates within bulk and surface atoms. We also investigated the deformation behaviors of triple junctions. We found out that yield strength of triple junction structure is quite close to the strength of NP structure. This means that deformation behavior of the NP system can be represented as a function of junctions rather than only single ligaments.