Study On The Preparation Process Of Graphene Reinforced 6061 Aluminum Matrix Composites

In this paper,graphene reinforced 6061aluminum matrix composites are prepared by vacuum hot pressing sintering.Copper is coated on the surface of graphene by electroless plating,that is,copper plated graphene reinforcement phase.Then,copper plated graphene and 6061 aluminum alloy powder are mixed evenly by a three-dimensional mixer,and aluminum matrix composites with different copper plated graphene reinforcement phase are prepared by powder metallurgy.The microstructure and mechanical properties were analyzed and compared.First,the copper plated graphite aluminum composite powder with different content is mixed,and then it is heat treated after vacuum hot pressing and sintering,and then it is hot rolled.After the blank is obtained,it is cut into the size required for the experiment.Finally,the experiments are carried out.The microstructure,graphene dispersion uniformity and interface bonding of the composite were observed by optical microscope,SEM,EDS,XRD and other equipment.It is found that graphene is mainly distributed at the grain boundary,low content of graphene can be uniformly distributed in the composite,the grain size of the composite becomes smaller,and no interfacial reaction product Al₄C₃ is found;High content graphene agglomerates in the matrix,and the distribution is uneven.The grain refining effect is obviously weakened.Al₄C₃is found in 1%content.0.5%graphene aluminum matrix composites showed the best grain size and dispersion.The properties of copper plated graphene reinforced aluminum matrix composites were analyzed by hardness test,tensile test,friction and wear test,and thermal expansion coefficient measurement.The hardness test data showed that the hardness of the composite increased first and then decreased with the increase of graphene content,and reached the maximum when the content of reinforcing phase was 0.75%.The analysis of tensile test data shows that the addition of graphene improves the tensile strength of the composite.When the content of graphene is 0.5%,the tensile strength of the composite is improved best;The yield strength reaches the peak value at 0.5%content,and the yield strength is also greatly improved when the content of graphene is too large（1%content）;The elongation after fracture decreases with the increase of graphene content;Both ductile fracture and brittle fracture were observed on the fracture surface.The results of friction and wear experiments show that the wear mechanism includes delamination wear and abrasive wear,and the composite with 0.5%content has the best wear resistance.The content of 0.5%has the lowest coefficient of thermal expansion,and has the most stable thermal expansion capacity with the increase of temperature.The pure 6061 aluminum alloy was compared with aluminum matrix composites with different copper plated graphene content（0.3%,0.5%,0.75%,1.0%）made by the same method.By comparing the experimental data,it is concluded that when the content of graphene is 0.5%,the comprehensive strengthening ability of the matrix is the best,and the tensile strength,yield strength,wear resistance and thermal expansion ability are the best.