Mechanical properties of honeycomb nanoporous silicon: a high strength and ductile structure

Abstract

There are remarkable studies geared towards developing mechanical analysis of nanoporous structures, while the size effect has been a major concern so far to improve strength or deformability. In this study, molecular dynamics simulations are utilized to study the pore shape effect on the mechanical behaviour of nanoporous silicon with circular, elliptical, square and hexagonal pore shapes. The influence of pore configuration on load transfer capabilities is studied for nanoporous silicon. A distinguished set of mechanical properties is observed on silicon with a hexagonal pore shape-resembling a honeycomb structure-with a high tensile strength and toughness. The study exhibits an improvement in the ductility through unique stress transformation in the hexagonal pore shape. In addition to the relative density, the potential to control the mechanical properties is demonstrated through the hexagon angle. Finally, a scaling law is developed for the mechanical behaviour of honeycomb nanoporous silicon. In addition to their outstanding mechanical properties, the work provides further insight into the capability of nanoporous structures in sensing applications due to their high surface-to-volume ratios.