Study On The Electromechanical Properties Of Graphene-enhanced Copper Matrix Composites

At present,the increasing demand for industrial field with excellent mechanical and electrical properties of high strength and high conductivity copper based composites.However,it was found that the improvement of mechanical properties of copper matrix composites would reduce their electrical properties.Therefore,improving the mechanical and electrical properties of copper matrix composites at the same time is a hot and difficult topic in current research.Graphene has excellent mechanical and electrical properties and is an ideal reinforcement material.In this paper,the mechanical and electrical properties of graphene-doped copper matrix(Cu-G)composites were studied by first-principles calculation,and the mechanical properties of Cu-G composites during tensile process were simulated.The properties of materials are closely related to the state of interfacial bonding.The addition of Ni/Co elements into Cu-G composites may lead to better bonding between graphene and copper,thus enabling the reinforced graphene to give full play to its excellent properties and obtain more excellent comprehensive properties of Cu-G composites.Therefore,the mechanical and electrical properties of Cu-G composites with Co/Ni impurities were studied by first-principles calculation,and the mechanical properties of Ni/Co doped Cu-G composites during tension and compression were simulated.Furthermore,the effect of Ni/Co doping on the microstructure and electronic structure of the Cu-G interface was studied,and the micro-mechanism of the effect of Ni/Co doping on the bonding properties of the Cu-G interface was revealed.In view of the fact that defects at the interface,such as vacancies,also affect the interface bonding between graphene and copper,the effect of vacancy defects coexisting with Co doping on the interface bonding was studied by the same method.The results are as follows:Firstly,the binding energy(-1.73 eV),electronic density and mechanical properties of Cu-G composites doped with graphene were studied by first-principles.The results show that graphene will bond with Cu matrix.Graphene can play a synergistic role in the stretching process of Cu-G composites,and promote the parallel tensile strength of composites to reach 13 in the x and y directions respectively.12.5 GPa.At the same time,the Young's modulus of pure Cu system and Cu-G composite in all directions is Cu(x)116GPa,Cu(y)125GPa,Cu(z)132GPa,Cu-G(x)221GPa,Cu-G(y)203GPa,Cu-G(z)189GPa,the Young's modulus of Cu-G composites is improved,and Cu-G composites have better mechanical properties than pure Cu.Secondly,the influence of Ni/Co on the electromechanical properties of Cu-G composite was investigated by first principles.The compressive strength of Ni(Co)doped Cu-G composites is higher than that of Cu-G composites,but the tensile strength decreases.Finally,the effect of substitution of Ni/Co atoms for Cu atoms on the interfacial bonding of Cu-G composites was studied by first-principles calculation.The calculation results show that the addition of Ni/Co elements can provide a force for the bonding between Cu and graphene,and effectively improve the bonding between Cu and G.At the same time,low concentration of Ni or Co atoms doping is more conducive to the bonding of Cu-G interface.Further studies show that C/Cu vacancy defects at the interface can also promote the interface bonding between Cu and G.The interaction between Co atom doping and C vacancy can maximize the bonding between graphene and Cu layers at the interface of Cu-G composites.Therefore,in the preparation of Co-doped Cu-G composites,the construction of C/Cu vacancy defects at the interface is helpful to enhance the interface bonding,the Cu-G interface can be more firmly bonded,graphene can give full play to excellent comprehensive properties,improve the properties of Cu-based composites,and obtain more excellent Cu-based composites.