Molecular dynamics simulation studies on the influence of aspect ratio on tensile deformation and failure behaviour of (100) copper nanowires

P Rohith and G Sainath and BK Choudhary, COMPUTATIONAL MATERIALS SCIENCE, 138, 34-41 (2017).

DOI: 10.1016/j.commatsci.2017.06.019

Molecular dynamics (MD) simulations have been performed to understand the influence of aspect ratio on tensile deformation and failure behaviour of (100) Cu nanowires with square cross-section at 10 K. In the present investigation, the aspect ratio (defined as nanowire length to cross-section width ratio) was varied from 0.5 to 30 in two different ways. In the first instance, cross-section width was varied from 43.4 to 0.72 nm for constant nanowire length of 21.69 nm, while in other, nanowire length was varied from 3.61 to 216.9 nm for constant cross- section width of 7.23 nm. The simulation results indicated that the Young's modulus and yield strength have been sensitive mainly to nanowire cross-section width and remains independent of nanowire length. Irrespective of varying length or cross-section width, all the nanowires deformed by the slip of 1/6 (112) partial dislocations and failed in ductile manner. Strain to failure (ductility) has been sensitive to both the nanowire length and cross-section width. The variations in tensile ductility with aspect ratio exhibited a rapid decrease at low aspect ratio followed by saturation at high aspect ratio. In the case of nanowires with varying cross-section width, high ductility at low aspect ratio arises mainly from high pre-and post-necking deformation. On the other hand, significantly higher post-necking deformation contributes to high ductility at low aspect ratio in nanowires with varying length. (C) 2017 Elsevier B.V. All rights reserved.

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