Compression and shear behavior of ultrathin coated nanoporous gold: A molecular dynamics study

This paper investigates the compressive and shear properties of nanoporous gold (np-Au) coated with different ultrathin metallic materials (i.e., platinum and silver) via molecular dynamics simulations. Atomistic models used for the geometric representation of coated and uncoated np-Au structures are generated through a modeling technique based on the Voronoi tessellation method. Three different coating thickness values are used to examine the role of thickness for the coating performance under compressive and shear loading by comparing the mechanical characteristics of the atomistic models such as Young's modulus, yield, and ultimate strengths. Moreover, adaptive common neighbor analyses are carried out by monitoring the evolution of the crystal structure of the specimens during the loading process. In this way, the deformation mechanisms of coated and uncoated nanoporous specimens are identified thoroughly. As a key finding from the simulation results, it is observed that the mechanical properties of np-Au are crucially dependent on the type of the coating material. However, a significant improvement on the toughness within the plastic regime is demonstrated for all types of coating materials and loading conditions.