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Abstract One-dimensional nanomaterials have different mechanical properties from macroscopic materials and have broad application prospects in micro and nano devices. The effects of pre-torsion degree, aspect ratio of nanorods and tensile strain rate on the tensile behavior of Pre-torsional single crystal copper nanorods were studied by molecular dynamics. The simulation results show that, at higher strain rates, pre-torsional deformation will reduce the yield strength of the axially <100> oriented nanorods, but will improve the tensile flow stress. By analyzing the evolution process of dislocation structure, it is found that the improvement of flow stress is due to the obstruction of dislocation movement by the initial dislocation network provided by pre-torsion deformation for the nanorods during the tensile process. With the increase of the pre-torsion degree, the initial dislocation density increases first and then decreases, which is reflected in the approximate change trend of the average plastic flow stress. Because the initial dislocation net will relieve the local stress concentration during the stretching process of the nanorods, the enhancement effect of pre-torsion on the tensile flow stress increases with the increase of the aspect ratio of the nanorods. At low strain rates, the dislocations produced by pre-torsion will alleviate dislocation starvation and reduce the flow stress of the nanorods compared with that of high strain rate. The tensile behavior of pre-torsional single crystal copper nanorod has been systematically studied, which is expected to provide theoretical support for understanding the plastic deformation mechanism of nanorods under complex loadings.
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Received: 03 January 2023
Published: 23 October 2023
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2023, Vol. 44 
