Molecular Dynamics Simulations of Aluminum Foams under Tension: Influence of Oxidation

For materials with high surface-to-volume ratio and high oxygen affinity, oxide layers will significantly change the material properties. However, oxidation effects have not been studied for metal nanofoams, which have many applications because of their light weight and high stiffness. We use molecular dynamics simulations to show that oxidized aluminum nanofoams possess significantly improved ductility without reduction in tensile strength. The Al–O interface leads to an increased defect nucleation rate at the oxide interface, preventing localized deformation. At the same time, the enthalpy of mixing between aluminium and oxygen decreases for increasing O concentrations, reaching a minimum at the stoichiometric ratio of Al₂O₃, resulting in stabilized bonds and increased strength.