Molecular Dynamics Simulation On Nano-copper And Its Nano-alloy Under Torsion

In the production activities of modern society,nano-copper and its alloy are widely used in various fields due to their more excellent properties.The molecular dynamics simulation method is illustrated systematically and is used to study the copper and its alloy nanowires in this paper,in order to explore the deformation mechanisms of nanowires under torsion and the influence of different factors on its mechanical properties.In this paper,a basic model of cylindrical single crystal copper nanowires is constructed and its deformation mechanism during torsion is analyzed.In combination with the changes in the microstructure of the crystal,the mechanical properties is investigated in detail.The torsional deformation process of nanowires is divided into three phases: the elastic phase,the plastic phase,and the cyclic deformation phase.The crystal has accumulated a lot of energy under the work of torsion force in the elastic phase and the internal lattice structure has not been damaged.Slip between the lattices begins in the plastic phase,dislocations appear on the surface and extend along the slip surface into the nanowire,and the torque and average shear stress of the model also decrease rapidly.In addition,the hollow single-crystal copper nanowires and copper alloy nanowires are carried out by molecular dynamics simulations.It is found that the dislocation tangling formed due to the lattice mismatch and void will affect the stability and torsional deformation of the nanowires.The effects of different factors on the deformation mechanism and mechanical properties of the nanowires are analyzed by changing the nanowires' size,torsion rate,and temperature.It is found in this work that the length of the nanowires has an effect on the elastic coefficient of the material.The mechanical properties of the nanowires show a small strengthening effect at higher torsional rates.And the atomic thermal movement is more intense at high temperatures,the dislocations in the nanowires will be form easier.The material's ability to resist elastic deformation is greatly reduced.This work provides a theoretical reference for further exploring the elastoplastic deformation mechanism of nano-copper and alloy.