Abstract
We apply molecular dynamics simulations to investigate the mechanical properties and atomistic deformation mechanisms of nanoporous gallium selenide (NPGS) nanosheets under uniaxial tension. The NPGS membranes structure-mechanical property correlation is investigated, especially the influences of temperature, neck width, pore shape, relative density, pore size, and strain rate. This work analyses the structural progression, initiation, fracture, brittle failure, Young's modulus, ultimate strength, fracture strain, material toughness, and critical energy release rate. In most tensile cases, crack initiates at high-stress concentration regions such as pore edges or pore corners. The crack propagates in the perpendicular with tension direction and especially prefers to spread in the zigzag directions of membranes. We also find that the increasing temperature improves the atom kinetic energy, accelerating the fracture process and significantly reducing the material mechanical properties. The relative density is a particular essential parameter to determine material mechanical properties. Likewise, the size effect of neck width indicates both material characteristics, including "smaller is tougher" and "smaller is stronger". Pore shape, notably diamond-pore, influences the stress distribution and stress absorption due to different tensile neck widths, leading to different mechanical responses, especially the material toughness. However, some material mechanical parameters were not much affected by some symmetrical pore shapes and strain rates. Remarkably, the stress distribution in the loading direction notably decreases the material mechanical performance. We also estimate the function between material mechanical properties and relative density or neck width as scaling laws to predict the mechanical properties of the NPGS nanosheets. The study results in an additional emphasis on mechanical behaviors and potentially expedites the promising applications of NPGS membranes.
NSTL
Elsevier