Study On The Structure And Properties Of Three-dimensional CNTs/Cu Skeleton Reinforced Copper Matrix Composite

Carbon nanotubes(CNTs)are considered as one of the most suitable reinforcements for copper-based composites because of their unique structure and excellent comprehensive properties.The uniform distribution of CNTs into the copper matrix can greatly improve the strength of the composite,but often at the expense of plasticity and electrical conductivity.In this paper,based on the designability of the structure and properties of composite materials,the three-dimensional structure of the copper matrix and the distribution of reinforcements are used to intersperse pure copper and high-strength reinforcement materials with excellent electrical and thermal conductivity and plasticity in copper matrix composites,so as to achieve the integration of structure and function of copper matrix composites.The main research of this experiment is as follows:(1)A three-dimensional CNTs/Cu_f skeleton with uniform CNTs dispersion was prepared by an electrodeposition process,and CNTs/Cu_f(?)Cu composites with excellent mechanical properties,electrical conductivity and densities were obtained by filling with pure copper powder and rapid sintering by SPS.The CNTs/Cu_f(?)Cu composites exhibited good mechanical properties(tensile and yield strengths of 366.7 MPa and 200MPa,respectively;elongation of 31.78%)and strengthening efficiency(R=138.1)when the CNTs content was 0.2414 vol%.Also the electrical conductivity reached 93.3%IACS.(2)Analysis of the electrochemical properties of CNTs/Cu_f(?)Cu composites reveals that the CNTs/Cu_f(?)Cu composites have the best corrosion resistance when the CNTs is 0.2414 vol.%,and the corrosion rate is reduced by 71.9%and 49.1%compared to Cu and Cu_f(?)Cu materials,respectively.(3)To improve the mechanical properties and electrical conductivity of the composite,the CNTs content of 0.2414vol%was cold rolled and annealed by 20%,40%and 60%.When the deformation amount was 40%,the composite had better mechanical properties when the tensile direction and rolling direction were the same,and its tensile strength and yield strength reached 656 MPa and 580 MPa,respectively,while the elongation was only 10.1%.The composites with 40%deformation were annealed at different temperatures,and the strength gradually decreased while the plasticity increased.When the annealing temperature was 400℃,the YS and UTS with elongation reached 255 MPa,379 MPa and 37.5%,respectively,and the strengthening efficiency was 1.87 times higher than that of the sintered state composites,with an electrical conductivity of 95.2%IACS.After subjecting the composites with different contents to the same process,the strength and plasticity were significantly improved compared with the sintered state composites with the same contents.(4)The effects of random orientation and orientation arrangement of CNTs on the load transfer process of the composites were numerically simulated,and the simulation results showed that CNTs aligned along the tensile direction had faster stress response and contributed the most in the load transfer process,which further provided a theoretical basis for the preparation of reinforced composites with oriented CNTs.Then,by theoretically calculating the strengthening mechanisms in the sintered state and after rolling and annealing,the calculations show that load transfer and dislocation strengthening contribute the most to the composites.