Oxidation induced softening in Al nanowires

The mechanical properties of metallic nanowires depend dramatically on the atmospheric conditions. Molecular-dynamics simulations with ReaxFF were conducted to study tensile elastic deformation of oxidized Al nanowires. The thin amorphous oxide shell formed around Al nanowires had a very low Young's modulus of 26 GPa, due to its low density and low Al-O coordination. Consequently, for diameters less than 100 nm, the composite Young's modulus of oxide-covered Al nanowires showed a size dependence implying that in this case smaller is softer. The model developed also explained the discrepancies in the reported modulus values of nanometer-scale Al thin films. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4790181]