Size-dependent elastic properties of Au nanowires under bending and tension-Surfaces versus core nonlinearity
ZJ Wang and C Liu and ZG Li and TY Zhang, JOURNAL OF APPLIED PHYSICS, 108, 083506 (2010).
The present work investigates contributions from surfaces and core nonlinearity to the size-dependent elastic properties of nanowires under bending and tension-compression. When a nanowire is formed by removing it from its parent bulk material, relaxation occurs inevitably because of high energy of newly created surfaces or born high surface eigenstress. Relaxation-induced initial strain could be large and nonlinear, which causes the size-dependent elastic properties of nanowires. If relaxation-induced initial strain is small and linear, the size-dependent elastic properties of nanowires are caused by surface Young's modulus. The eigenstress model for surface stress of solids Zhang et al. Phys. Rev. B 81, 195427 (2010) is further developed here for nanowires under bending and tension-compression. The developed eigenstress model leads to general scaling laws for nanowires under bending and tension-compression. In the scaling laws, there are the surface and nonlinearity factors, which measure quantitatively the contributions of surfaces and core nonlinearity, respectively, to the nominal Young's modulus of nanowires. Atomistic simulations on Au 001 nanowires verify the theoretical predictions. (C) 2010 American Institute of Physics. doi: 10.1063/1.3493264
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