Fabrication And Mechanism Of Graphene/Copper Matrix Composites Based On FSP Technology

Aiming at the problem of low strength and hardness of copper materials,this paper has carried out the research on the preparation mechanism of graphene/copper and composite materials by FSP,which explores the preparation process of composite materials,and studies the changing regularity of micro-structural characteristics,tensile strength,hardness and electrical conductivity of composite materials at different revolving speeds and with different adding amount of graphene.The fracture mechanism of composite materials is also studied in this research.The results show that the effects of graphene on the copper matrix are mainly reflected in the load transfer and the hindrance of dislocation movement and grain boundary growth in the copper matrix.The analysis of structure of the graphene/copper composites shows that with the introduction of graphene,the grains in the NZ have been significantly refined.The reason of grain refinement is the mechanical stirring of the stirring head and the hindering effect of graphene on grain growth during recrystallization.In the tensile test of the material,the graphene-added group has an overall higher tensile strength than that of the base material group.The maximum tensile strength can reach up to 277.49MPa,which is about 5%higher than base material.When the addition of graphene is 0.56%vol,the tensile strength is lower than that of the base material.The fracture mode of the composite materials is ductile-brittle mixed fracture mode.EDS results in the brittle fracture zone show that the graphene content in the brittle fracture zone is significantly higher than that in the ductile fracture zone,which leads to material's brittle fracture in this zone.Through hardness test,the hardness improvement of the graphene/copper composites is mainly in the NZ.The material recrystallizes due to the heat input during the processing,the hardness of the composites in the group without graphene decreased as a whole.In the groups with graphene addition,the hardness of the NZ increased.The hardness decreased first and then increased with the increase of the rotational speed,and the hardness increased first and then decreased with the increase of the graphene addition amount.In the electrical conductivity experiment,the group of 0.42%vol graphene addition and at the revolving speed of 650r/min has the best electrical conductivity.The conductivity is8.52×10~7S/m,which is about 5.7%improved than that of the base material.