Investigation on mechanical properties of polycrystalline W nanowire

Metal nanowires are stirring the attention of scientific world because of their many unique properties. W single crystal nanowires, with bcc crystal configuration, have become focus of many studies due to lack of complete insight of their mechanical deformation. However, polycrystalline W nanowires are not thoroughly studied yet. In this work, molecular dynamics simulation is used to identify different aspects of deformation and plasticity of polycrystalline W nanowire using EAM potential and a constant strain rate of 10(9) s(-1). Impact of grain size, diameter, and temperature on the elastic properties is analyzed. Average grain size is varied from 4.63 nm to 25 nm keeping the diameter constant at 5 nm and temperature at 10 K. Diameter of the nanowire is varied from 2 to 5 nm keeping the average grain size and length to diameter ratio constant while temperature was changed from 10 K to 500 K maintaining fixed diameter and grain size. It is observed that inverse Hall-Petch behavior dominates the plasticity in polycrystalline nanowires and grain boundary sliding becomes the dominating mechanism of plasticity with a critical grain size. Nanowires with shorter diameter are found to be stronger and elevated temperature weakens the nanowire irrespective of the grain size. (C) 2017 Elsevier B.V. All rights reserved.