Amorphous oxide layers form rapidly on aluminum surfaces, even under vacuum conditions. The growth of amorphous oxide structures on pure aluminum surfaces leads to the formation of defects and stress development during the oxidation process. We investigate the phenomenon by reactive molecular dynamics simulations including COMB3 and ReaxFF. Established systematic studies arm to a better understanding of the stresses caused by the process. Surfaces of aluminum single crystals with different crystal orientations such as <100>, <111>, <110>, <211> and aluminum icosahedral nanoparticles are exposed to an environment with different oxide pressures. The oxidized and deoxidized structures will be used for mechanical tests including nanoindentation and nanoscratching. Together with the stresses, the atomistic structure, bonds from the process and the self-limiting oxidation will be analyzed. These findings provide a solid evidence base for the design of high-performance metallic materials with improved mechanical properties.