Rolling Simulation Of Composite And Experimental Research Of Multilayer Copper Foil

Copper and copper alloys are good conductors widely used at this stage.In order to reduce the loss in current conduction,people are committed to improving their electrical conductivity.Graphene has excellent mechanical,physical,and chemical properties.This research focuses on the development of copper and graphene.The composite process of high-conductivity conductors has been studied from macroscopic preparation and microscopic mechanism analysis.Experimental studies have found that the copper-based graphene foil prepared by the chemical vapor deposition(CVD)method is formed by roll bonding.It has ultrahigh conductivity and excellent mechanical properties and can be widely used in various fields,such as high-performance cables,superconductivity,and high-speed rail.In the early stage,the size of high-conductivity and high-strength composite conductor materials prepared by static pressure,sheath rolling,and other methods is usually tiny.It is challenging to form a large-scale application.In order to achieve large-scale production,this thesis uses computational simulation techniques to study the critical technical issues of graphene copper foil rolling and compounding.Based on the previous research,the Arrhenius constitutive model of 99.99% pure copper at 200 ℃,400 ℃,and 600 ℃ was constructed.The rolling composite process of 10 layers of graphene copper foil with a thickness of 25 μm was simulated using DEFORM finite element software;the stress fields,strain fields,temperature fields,and velocity fields in the compound rolling process are analyzed.The combined conditions of simulated rolling include rolling temperatures of 200 ℃,400 ℃,and 600 ℃,rolling reduction rates of 10%,15%,and 20%,and rolling speeds of 0.15 m/s,0.2 m/s,and 0.25 m/s.Through simulation,it is found that the copper foil composite is better when the rolling speed is 0.2 m/s,the reduction rate is 15%,and the rolling temperature is 600 ℃.The simulation results are compared with the performance of the copper conductor produced by the sheath rolling method under the corresponding conditions,which shows that the optimal process conditions predicted by the simulation are reasonable.In order to further study the mechanical properties of microcosmic copper graphene and the deformation mechanism between them,a copper graphene model with a size of 20nm×20nm×20nm was established using MD simulation.Firstly,the microscopic deformation mechanism of copper graphene at different temperatures(100 ℃,200 ℃,400 ℃,600 ℃,and 800 ℃)was studied,and single crystal copper at400 ℃ was used as a control.The results showed that the yield strength of copper graphene was 2.1 GPa,the yield strength of pure copper under this condition was 1.52 GPa,and the yield strength increased by 27.6%,indicating that the addition of graphene can enhance the mechanical properties of copper-based materials.As the temperature increases,the yield strength of copper-based graphene decrease from 2.65 GPa to 1.53 GPa,a reduction of 41%.The decline in mechanical properties is mainly due to the transformation of the crystal structure and the formation of dislocations,which is different from crystalline copper under compressing.Due to the effect of graphene,dislocations will be emitted near the interface between graphene and copper.Secondly,the mechanical properties of copper graphene at different strain rates of 0.00025/ps,0.0005/ps,0.00075/ps,and 0.001/ps were studied.The results showed that the limit of yield strength increased from 1.74 GPa to 1.81 Gpa with the increase of strain rate at600 ℃;With the decrease of yield strength,it can be seen that the dislocation increases and the movement of the leading dislocation dominate the deformation in the plastic stage.Process simulation and molecular dynamics microscopic research provide reasonable technical support for developing a rolling composite process of graphene copper foil.