Research On The Preparation, Structure And Performance Of Carbon Nanomaterials Reinforced Copper Matrix Composites

Due to the high Young's modulus,high strength,high hardness,excellent electrical and thermal conductivities,carbon nanofillers have been considered as ideal reinforcements for Cu matrix composites.Carbon nanofillers mainly include one-dimensional carbon nanotubes?CNTs?and two-dimensional graphene?GP?.However,there are several problems which are the easy agglomeration of carbon nanofillers,poor wettability between Cu matrix and carbon nanofillers and weak interface bonding,causing the strengthening effect of carbon nanofillers in Cu matrix composites significantly lower than that of the theoretical value.In addition,weak interfacial bonding can greatly cause electron scattering and affect the conductivity of carbon nanofillers/Cu composites.Hence,in this paper,the preparation,microstructure and composites'properties are studied based on the starting points of the structural design,carbon nanofillers'dispersion and interface bonding of carbon nanofillers/Cu composites.There are the main results:?1?The effects of hierarchical structure,CNT-reduced graphene oxide?RGO?network hybrids and in-situ grown Cu₂O nanoparticles on the properties of the composites were investigated by an improved molecular-level method?MLM?.It has been discovered that the ultimate tensile strength?UTS?of 2.5 vol.%CNT-RGO/Cu composite was 601 MP,while the UTS of 2.5 vol.%RGO/Cu composite was 450 MPa with the elongation percentage of 9.33%.At the same time,they maintained the conductivity of 83%and 85%IACS,respectively.?2?Nano-CuO particles were decorated on the surface of CNTs by chemical deposition method,and then the Cu matrix composite enhanced by decorated CNTs?Cu O@CNTs?was prepared by powder metallurgy.The effects of Cu O nanoparticles on the uniform dispersion of CNTs in Cu matrix and interface bonding between Cu matrix and CNTs were studied.In addition,the effects of nano-Cu O particles?Reduced to nano-Cu particles during the reduction process?on the surface and inside of CNTs on the mechanical and electrical properties of Cu matrix composite were also studied.Research indicates that the UTS of Cu@CNT/Cu composite was about 272 MPa,which was higher than that of CNT/Cu composite??230 MPa?.And the conductivity of Cu@CNT/Cu composite was about 93.6%IACS,higher than that of CNT/Cu composite??90.9%IACS?.?3?Through the analysis of the strengthening mechanisms,it was found that the increasing UTS of Cu@CNT/Cu composite mainly comes from load transfer and Orowan strengthening mechanisms.The contribution value of Orowan strengthening to the UTS of Cu@CNT/Cu composite was 49.4 MPa.And the contribution value of load transfer to the UTS of Cu@CNT/Cu composite was 49 MPa.At the same time,through the analysis of the conducting mechanisms,it was found that the main reasons why the conductivity of CNT/Cu composite is lower than that of pure Cu are the interfaces scattering and the grain boundaries scattering.