Study On The Preparation Process And Performance Of CNTs/Cu Composite Wire

Copper,as the only metal that can produce a large amount of natural products,is widely used in electrical,light,mechanical,construction,national defense and other fields due to its good plasticity,excellent conductivity,thermal conductivity and corrosion resistance.However,with the development of science and technology and the progress of society,higher demands have been put forward on the room temperature strength and high temperature properties of copper.Carbon nanotubes(CNTs)are used as metal matrix reinforcement because of their excellent structure and properties.Great progress has been made in improving the mechanical properties of copper-based materials using carbon nanotubes as reinforcement phase.Carbon nanotubes(CNTs)-reinforced copper-based composites have broad prospects in many fields.Many methods have been used to prepare CNTs/Cu composites,but different methods have different defects.Therefore,a new electrostatic adsorption-spray drying process is used to prepare composite powders with different carbon nanotube contents.CNTs/Cu composite wire was prepared by vacuum sintering,hot extrusion and drawing.The microstructure,hardness,conductivity and tensile strength of the materials were tested by metallographic microscope,scanning electron microscope,hardness tester,eddy current conductivity tester,tensile tester,etc.Finally,a suitable carbon nanotube content parameter is obtained.After determining the better carbon nanotube content parameters,we studied the influence of different sintering methods on the microstructure and properties of the materials by changing the sintering methods.In addition to the above tests,the composites prepared by different sintering methods were observed by transmission electron microscopy,and the reinforcement mechanism was analyzed to a certain extent.The results showed that:The electrostatic adsorption-spray drying process can make carbon nanotubes distribute uniformly in copper matrix to a certain extent when the content of carbon nanotubes is low,and have better interfacial binding property,at the same time,it can guarantee the integrity of carbon nanotubes.Short production process,high efficiency.However,with the content of carbon nanotubes,its dispersion is difficult to be guaranteed.When the content of carbon nanotubes is 0.4 wt.%,the material has excellent properties.By improving the density,grain size,dispersion of carbon nanotubes,the orientation of grains and carbon nanotubes,the bar and wire produced by hot extrusion and drawing can improve the mechanical properties and electrical properties of carbon nanotubes,respectively.The tensile strength of block,bar and wire are 210 MPA and 350 MPA,respectively.The electrical conductivity of block and wire are 64.3%IACS and 86.9 IACS,respectively.The SPS sintering method improves the density and grain size of the material greatly,and improves the properties of the prepared bulk material and the subsequent extruded bar to a certain extent.The hardness and tensile strength of the bulk and bar are raised to 92.3HV and 108.8 HVrespectively,and the tensile strength to 262 MPa and 323 MPa,respectively.However,the microstructure and properties of the material tend to be the same after the large plastic deformation after drawing.It can be observed by TEM that when the content of carbon nanotubes is suitable,the matrix is dispersed well,the interface with copper matrix becomes blurred after hot extrusion and drawing,and the Cu-O-C interface with strong binding property may be formed.When the content of carbon nanotubes is high,the carbon nanotubes exhibit a lot of agglomeration and may fall off from the copper matrix because of the poor interfacial bonding.Finally,the reinforcement mechanism of composites is analyzed.