Mechanical Properties Of The Carbon Nanotube-wrapped Gold Nanowires

With the continuous development of micro-nanotechnology,carbon nanotubes filled with various materials can form a variety of strange structures,which has aroused considerable interest among researchers.Nano-materials have attracted much attention in the structure and mechanical properties of carbon nanotubes.Interestingly,carbon nanotubes can also be used as a natural mould for the preparation of nanowires.The effect of carbon nanotubes will inevitably cause changes in the microstructure and properties of nanowires.In this paper,molecular dynamics methods were used to study the mechanical properties of tensile and compressive effects of the carbon nanotubewrapped gold nanowires.The results will provide crucial theoretical understanding for the mechanical properties of gold nanowires based on carbon nanotubes.Firstly,compared with the gold nanowires in the free state,the tensile properties of the carbon nanotube-wrapped gold nanowires were studied.The results show that the gold nanowires in the free state are the standard face-centered cubic structures,and the gold nanowires coated with carbon nanotubes show a layered structure.With the increase of the cross-section radius,the layered structure changes from less to more,that is,the layered structure is more noticeable.The gold nanowire coated with carbon nanotubes and free state gold nanowires has little difference in maximum stress,but its resistance to elastic deformation is much more excellent than that of free state gold nanowires.The free-state gold nanowire tensile deformation microcosmic mechanism: the free state of the gold nanowire is a face-centered cubic structure,and the closepacked surface of the face-centered cubic structure is {111} plane.That is,the atoms are densest in the <110> direction of the {111} plane and the slip occurs in the densest direction of the atoms.The atoms slide along dislocation lines until the gold nanowires break.The microscopic mechanism of tensile deformation of gold nanowires coated by carbon nanotubes: with the increase of strain,the stress reaches a specific strength,which makes the surface atoms have higher energy and speed.This causes the atomic movement of the surface atoms to lower internal energy,eventually leading to the appearance of dislocation defects and atomic lattice necking,until the breakage of the gold nanowires.Secondly,compared with the gold nanowires in the free state,the compression properties of the carbon nanotube-wrapped gold nanowires were studied.The results show that the elastic modulus and maximum stress of the gold nanowire coated by carbon nanotubes are larger than those of gold nanowires in the free state.In the plastic deformation stage,the maximum stress of the carbon nanotube-coated gold nanowires is slightly larger than that of the free-state gold nanowires.This shows that the gold nanowire coated with carbon nanotubes resists elastic deformation and the maximum stress during the elastic deformation stage is higher than that of the free gold nanowires.The maximum stress of the gold nanowire coated with carbon nanotubes in the plastic deformation stage is slightly higher than that of free state gold nanowires.The freestate gold nanowire compression deformation microcosmic mechanism: the free state of the gold nanowire is a face-centered cubic structure,and the close-packed surface of the face-centered cubic structure is {111} plane.That is,the atoms are densest in the <110> direction of the {111} plane and the slip occurs in the densest direction of the atoms.The atoms gradually slipped to the middle along the left dislocation line and the right dislocation line until the gold nanowire completely lost its bearing capacity.The microscopic mechanism of compression deformation of gold nanowires coated by carbon nanotubes: with the increase of strain,the stress reaches a particular strength,making the surface atoms have higher energy and speed.This causes the surface atoms to move outwards,eventually causing dislocation defects and atoms to accumulate on the right until the gold nanowires completely lose their bearing capacity.