Molecular statics simulations of the size-dependent mechanical properties of copper nanofilms under shear loading
XR Zhuo and HG Beom, COMPUTATIONAL MATERIALS SCIENCE, 99, 390-395 (2015).
Molecular statics simulations are conducted on single-crystal copper nanofilms subjected to shear loading to examine the effect of thickness on the mechanical properties of nanofilms. Simulation results show that not only the yield strength but also the shear modulus increases with decreasing film thickness. In order to better relate the yield strength of a copper nanofilm to its thickness, a Hall-Petch-like fitting function is proposed to predict the variation of yield strength with film thickness. The initial yield is found to be associated with the nucleation of dislocations. The energy required for the first nucleation of dislocations is calculated and plotted as a function of film thickness to elucidate the origin of the thickness effect on yield strength. In addition, the production of vacancy clusters is also found to depend on film thickness and three new patterns of vacancy clusters are observed in our simulations. (C) 2015 Elsevier B.V. All rights reserved.
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