Mechanical behaviour of nanoporous metals reinforced with carbon based nanomaterials

Nanomaterials have gained attention as nano-science and nanotechnology improves. Nanoporous (np) metals have attracted considerable attention owing to their cellular morphological features at atomistic scale which yield ultra-high specific surface area awarding a great potential to be employed in diverse applications such as catalytic, electrocatalytic, sensing, mechanical and optical. As one of the carbon based nanostructures, fullerenes, nanoribbons and CNTs are also another type of outstanding nanomaterials that have been extensively investigated due to their remarkable chemical, mechanical and optical properties. In this study, the idea of improving the mechanical behavior of nanoporous metals by inclusion of the carbon based nanomaterials, which offers a new metal-carbon nanocomposite material, is examined and discussed. With this motivation, tensile and compressive mechanical behavior of nanoporous metals reinforced with carbon based nanomaterials is investigated by classical molecular dynamics (MD) simulations. Atomistic models of the nanoporous metals with ultra-thin ligaments are obtained through a stochastic process simply based on the Voronoi tessellation which has been used previously in literature. According to this technique, quasi-random points are created that depends on determined distance and volume. Voronoi volumes or surfaces are obtained by using these points with Voronoi tessellation method and line segmets occur. Then, the line segments are turned into volumetric structure. Afterwards, this volumetric structure is filled with gold atoms. Therefore, np atomic skeleton are obtained. Finally, carbon based nanomaterials are added into the cellular voids to obtain final atomistic configurations for the numerical tensile and compressive tests. Several numerical specimens are prepared with different type of carbon based nanomaterials such as CNTs, nanoribbons and, fullerenes per cell. LAMMPS (Large-scale Atomic/Molecular Massively Parallel Simulator) code was used to perform classical MD simulations to conduct uniaxial tension and compression experiments on np models filled by carbon based nanomaterials. The interactions between the metal atoms are modeled by using embedded atomic method (EAM) while adaptive intermolecular reactive empirical bond order (AIREBO) potential is employed for the interaction of carbon atoms. Furthermore, atomic interactions between the metal and carbon atoms are represented by Lennard-Jones potential with appropriate parameters. In conclusion, the ultimate goal of the study is to present the effects of carbon based nanomaterials embedded into the cellular structure of np metals on the tensile and compressive response of the porous metals. The results are believed to be informative and instructive for the experimentalists to synthesize hybrid nanoporous materials with improved properties and multifunctional characteristics.