Influence of oxide layers on plastic properties of metals: From atomistic to mesoscopic scale

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Since in oxidation-rich environments an oxide layer will form on metallic surfaces, the influence of oxidation on dislocation nucleation needs to be considered. This is particularly important for materials with high surface-to-volume ratio as porous matter and lightweight materials as aluminum. For the latter, even under high vacuum conditions, an oxide layer may form within seconds. This will influence the mechanical properties of materials because of increased dislocation nucleation due to increased activation volume and increased number of dislocation sites leading to enhanced ductility of nanocrystalline metals. The influence of oxidation on the mechanical properties of metals will be studied using molecular dynamics Since in oxidation-rich environments an oxide layer will form onsimulations considering the fundamental dependencies on oxygen concentration and temperature. The focus of this study will be primarily on the nucleation of dislocations for oxidized metals. The transition from the cracking behavior observed at the mesoscale, to the assisted-ductility behavior observed at the nano-scale will be analyzed. The atomistic simulations will be used to implement dislocation nucleation considering oxide layers in mesoscale dislocation dynamics of thin films using a stochastic model. Therewith, a physically reliable model for dislocation dynamics simulations of oxidized surfaces will be available acting on time scales accessible to experiments.