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

Abstract

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 Al 2 O 3 , resulting in stabilized bonds and increased strength.

Molecular dynamics simulations of the mechanical behavior of alumina coated aluminum nanowires under tension and compression

“…For the coated samples, the number of dislocations linearly increases between 10% and 15% strain and reach higher values. As shown before, 10,19 the Al-O interface leads to an increased number of dislocations sites. Note that this result is consistent with experiments of Au nanowhiskers coated by Al 2 O 3 via atomic layer deposition.…”

Atomistic Construction of Silicon Nitride Ceramic Fiber Molecular Model and Investigation of Its Mechanical Properties Based on Molecular Dynamics Simulations

“…From the data graph Figure 7 , Figure 8 and Figure 9 , it can be seen that compared to molecular models with densities of 2.0 and 1.8, the addition of a crystalline structure, regardless of the presence of a cross-linked transitional region, effectively enhances the tensile strength of the ceramic structure. The presence of the crosslinked transitional region efficiently transmits and disperses load stress, absorbing this part of the energy and utilizing the higher elastic modulus to organize crack propagation [ 30 ]. Therefore, X’s overall performance is stronger than Y’s.…”

Temperature-dependent magnetism in Fe foams via spin-lattice dynamics

“…Recently, variations of the magnetic moment with effective electronic density were studied for the surface of Fe nanoparticles [18]. Metallic nanofoams might suffer oxidation [35]. Fe surfaces might form magnetic oxides or form a magnetically dead thin layer [36,37].…”