Size and strain rate effects in tensile strength of penta-twinned Ag nanowires 
期刊名称Acta Mechanica Sinica
作者Xuan Zhang; Xiaoyan Li; Huajian Gao
摘要Penta-twinned Ag nanowires (pt-AgNWs) have recently attracted much attention due to their interesting mechanical and physical properties. Here we perform large-scale atomistic simulations to investigate the influence of sample size and strain rate on the tensile strength of pt-AgNWs. The simulation results show an apparent size effect in that the nanowire strength (defined as the critical stress for dislocation nucleation) increases with decreasing wire diameter. To account for such size effect, a theoretical model involving the interaction between an emerging dislocation and the twin boundary has been developed for the surface nucleation of dislocations. It is shown that the model predictions are in quantitative agreement with the results from atomistic simulations and previous experimental studies in the literatures. The simulations also reveal that nanowire strength is strain-rate dependent, which predicts an activation volume for dislocation nucleation in the range of 1-10b3, where b is the magnitude of the Burgers vector for a full dislocation.
关键词Penta-twinned nanowire; Size effect; Strain rate effect; Dislocation nucleation; Atomistic simulation
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作者地址1 Centre of Advanced Mechanics and Materials, Department of Engineering Mechanics, Tsinghua University, Beijing 10084, China;
2 School of Engineering, Brown University, Providence, Rohde Island 02912, USA

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