Research On The Influence Of Raw Material Composition On The Properties Of Carbon Nanotubes Reinforced Copper Matrix Composites

CNTs/Cu combines the advantages of high strength of CNTs and the virtue of copper's high conductivity.It is widely used in the high-speed electrified railway,microelectronics IC,aerospace and other frontier.The preparation of high strength and high conductivity CNTs/Cu composite materials is a hot spot in the field of material research in the world.At present the method of preparation of CNTs/Cu composites is mainly adopted powder metallurgy method,it has flexible ratio of raw materials,the material composition of the advantages of uniform.For that reason this article uses the high energy ball mill and vacuum hot pressing molding method for preparation of CNTs/Cu composite materials.With the literature reported that rare earth doped and refining matrix particle size can effectively improve the mechanical and electrical properties of copper matrix composites.Therefore,this article adopt the method of improving copper powder particle size and adding rare earth to increase the tensile strength and conductivity performance of CNTs/Cu composites.At first,this paper adopts the single factor method to study the different copper powder particle size on the CNTs/Cu composites and the effect of the tensile strength and electric conductivity.Through the theoretical calculation of composite powders and the analysis of composite microstructure observed by SEM,The results shows that with the copper powder granularity decreased from-200 mesh to-1000 mesh,composite powder for sintering driving force ratio is 1:3:5:7,the composite statistical average grain size from 36.7 microns reduce to 7.2 microns.CNTs/Cu composite material tensile strength increased from 182.37 MPa to 278.39 MPa,increased by 52.75%.Conductivity of CNTs/Cu shows a trend of decrease after the first increase.When the particle size less than 600 yard,conductivity of composites from the highest 91.85%IACS,reduce to 86.12%IACS.Then,the amount of different rare earth was studied by single factor method of CNTs/Cu composites and the effect of the tensile strength and electric conductivity.Through the analysis of composites tensile strength and electric conductivity performance found that increased with the addition of rare earth,It is helpful to improve the electrical conductivity of CNTs/Cu composite materials and tensile strength.When the rare earth addition amount of 0.05%reached the highest tensile strength and conductivity of composite materials it Respectively is 246.24 MPa and 92.16%IACS.It is not rare earth samples tensile strength increased by 11.4%,the conductivity increased by 10.3%.Through calculation of the ball mill powder XRD and SEM composite morphology observation and energy spectrum analysis found that a moderate amount of rare earth to join the enhancement effect is fine grains,and promote the CNTs uniform distribution.Finally,through the response surface central composite design(CCD)test method to get the raw material formula of CNTs/Cu composite materials,the mathematical model of tensile strength and electric conductivity.According to the model to get the best raw material composition for the tubes content 1 vol%,0.05 wt%for the amount of rare earths,600 mesh copper powder particle size.The CNTs/Cu composite materials tensile strength and electric conductivity respectively is 245.31 MPa,90.95%IACS.