Study On Preparation And Properties Of RGO/Cu Composites

Graphene,constituted by single atomic layer of sp2 hybrid orbital carbon atoms,is two-dimensional crystal structure with excellent electrical,optical,thermal and mechanical performance.As the reinforcement,it has been successfully used to prepare the graphene reinforced metal matrix composites,especially forcopper matrix composites.The tensile strength and hardness of copper matrix composite can be improved by doping graphene,however,how to improve the dispersion of graphene and elongation of graphene/copper composite is an key issues needed to resolve urgently.This paper uses the repressing and resintering process to prepare graphene /copper composite materials with ultrasonic and ball milling technology to improve the dispersion of graphene oxide,explores the effects of the addition of graphene oxide on the microstructure and properties of the composite;Based on orthogonal experiment analysis,preparation process parameter of RGO/Cu composite were optimized.The main conclusions are as followed.The microstructure analysis of Cu matrix composite reinforced by different reinforced phases show that the dispersion of RGO is more homogenization than that of C,CNT and Gr.This enhances the lubrication effect of carbon materials,which resulting in the high relative density(99.04%)of RGO/Cu composite.Due to the decrease of the scattering of electromagnetic wave resulting from uniform dispersion of RGO and the high relative density of the composites,the conductivity of RGO/Cu composites is the largest(91.64 IACS%).The addition of reinforcement phase improved microhardness and tensile strength of the composites(except graphite/copper composites).The microhardness and tensile strength of 0.5 wt.%RGO/Cu composite reach the highest value of 71.2 HV and 229.22 MPa,respectively,and having 23.6% and 25.35% increase compared with pure copper.The main strengthening mechanisms are fine-grain strengthening and dislocation strengthening.Because of the low Cu-C interface strength,RGO/Cu composite elongation(66.8%)is lower than that of pure copper(80.0%).The orthogonal experiment results show that the primary and secondary order of the influence of process parameters on the relative density of RGO/Cu Composites is:recompact pressure > first compact pressure > first sintering temperature > resintering temperature.The primary and secondary order of the influence of process parameters on the microhardness of RGO/Cu Composites is: first compact pressure > firstsintering temperature > recompact pressure> resintering temperature.Upon comprehensive consideration,the optimum preparation parameters of 0.5 wt.%RGO/Cu composites are obtained: the initial pressure of 600 MPa,the initial sintering temperature of 950 ?,the complex pressure of 1000 MPa,and the complex sintering temperature of 600 ?,the elongation of RGO/Cu composite is 66.8%.With the increase of GO content and beyond 0.5 wt.%,the agglomeration of RGO increase,and the relative density of RGO/Cu composites increased firstly and then decreased.The 0.5 wt.% RGO/Cu composite has the highest relative density of99.4%.The interfacial conduction of Cu-RGO-Cu increases the scattering of electromagnetic wave,which leads to the decrease of the conductivity of RGO/Cu composites with the increase of GO content,and the conductivity of 1.0 wt.%RGO/Cu composites decreases to 90.83 IACS%.The higher the GO content,the higher the microhardness.They are 68.4 HV(0.3 wt.%),71.2 HV(0.5 wt.%)and 80.6HV(1.0 wt.%),respectively.However,the low interface strength of Cu-RGO and RGO agglomeration result in that fracture mechanism RGO/Cu composite changes from ductile fracture(0.3-0.5 wt.%)into semi brittle fracture(1.0 wt.%).The tensile strength and elongation decreased with the increase of GO content,the 0.3 wt.%RGO/Cu composite is 76.7%.