Effects of ultrathin coating on the tensile behavior of nanoporous gold

In this study, the mechanical properties of nanoporous gold (np-Au) coated with different ultrathin metallic materials (i.e., platinum and silver) are studied through molecular dynamics simulations. A new atomistic modelling technique, which is based on the Voronoi tessellation method providing periodic atomistic specimens, is used for the geometric representation of np-Au structure. Three different coating thickness values are used to examine the role of thickness on the coating performance under tensile loading at a constant strain rate. Several parameters, including Young's modulus, yield, and ultimate strengths, are utilized to compare the mechanical characteristics of coated and uncoated np-Au specimens. Moreover, adaptive common neighbor analyses are performed on the specimens for the purpose of understanding the deformation mechanisms of coated and uncoated nanoporous specimens comprehensively by monitoring the microstructural evolution of the crystal structure of the specimens within the deformation process. As a main finding from the simulations, it is observed that the mechanical properties of np-Au are improved by coating independently of the coating material type. However, enhancements on the yield and ultimate strengths maintained by platinum coating are greater than those provided by the silver coating.