Deformation Behavior And Properties Of Copper Matrix Composites Reinforced By In-situ Grown Graphene

Due to the excellent mechanical and thermophysical properties,graphene reinforced copper-based composites have great prospects in the fields of electronic packaging and special wires.At present,effectively solving the uniform dispersion of graphene in the matrix is still a key bottleneck restricting the further application of composites for industrial applications.In addition,plastic deformation is a common method for the formation and application of composites.Therefore,it is of great significance to study the microstructure and properties of composites during the process of the deformation.In this work,graphene/copper composite was prepared by combining an in-situ method and SPS.And the effects of rolling and drawing deformation on the microstructure,texture and properties of comp osites were systematically studied.The effect of two solid carbon sources of naphthalene and naphthol on the growth of graphene on copper powders was compared.Compared with naphthalene,naphthol can be chemical adsorbed on copper powders,which not only can effectively prevent the copper powder from sintering agglomeration at high temperature,but also promote the growth of high quality graphene.Therefore,naphthol was used as the carbon source and the influence of growth process of graphene on copper powders was studied.It was found that the sp2 content of the graphene prepared at 800 oC for 1?20 min is about 80%,and the ID/IG value is 0.8?0.9.Among them,the ID/IG value was the lowest(0.85)and the content of sp2 carbon was the highest(82.6%)when the carbonization time was 10 min.0.7 vol.% graphene/copper composites were prepared by SPS.Studies have shown that graphene with a thick size is randomly distributed as-sintered composites.This paper firstly compares the microstructure of composites at different hot rolling temperatures of 400 oC,500 oC and 600 oC with a redution of 80%.It was found that the graphene in the composite can be significantly thinned when rolling at 500 oC.The microstructure of the composites with different rolling ratios shows that the graphene in the matrix undergoes fracture,orientation and thinning.Texture analysis of the as-rolled composite showed a strong shear texture at 500 oC.Therefore,the thinning of graphene may be caused by the formation of shear deformation at the interface in the composite.The study of tensile properties has shown that hot rolling can significantly improve the tensile properties of as-sintered composites.The tensile strength and elongation of the composite gradually increase with increasing rolling reducions.The main reason for the low strength and elongation of as-sintered composites is the large thickness of graphene.Hot rolling can promote the thinning and the alignment of graphene in composite.After rolling at 500 ° C by recution of 80%,the tensile strength of the composites with graphene volume fraction of 0.4%,0.7% and 1.4% were enhanced by 43%,62%,and 75% compared with pure copper matrix,respectively.The analysis of strengthening mechanism shows that the strengthening of load transfer,fine grain and thermal mismatch are the main strengthening mechanisms of composites.In addition,the as-rolled composites exhibit excellent tribological properties and electrical conductivity.Graphene/copper composite wire with volume fraction of 0.3 % was prepared by SPS,hot extrusion and drawing deformation.The microstructure,texture and properties of composites with different drawing reductions were studied.The results show that,with increasing drawing reducions,the grain size of the composite is continuously refined and the content of the recrystallized grain decreases first and then increases.When the drawing redcution is 99.7%,the percentage of the recrystallized grain is higher than 60%,indicating that the dynamic recrystallization is formed in the composite;The fibre texture of the composite changes from the initial <100> fibre texture to a stronger <111> and weaker <100> fibre textures;the tensile strength of the composite is 581.4 MPa,and the electrical conductivity is 45.9×10~6 S/m.