Study On Preparation And Performance Of Nano-phase Hybrid Reinforced Aluminum Matrix Composites

In this paper,graphene and SiC nanoparticles were coated by high energy ball milling to form a large number of graphene coated silicon carbide particles,that is,graphene-SiC nanoparticles composite reinforcement phase.Then graphene-SiC nanoparticles reinforced aluminum matrix composites were prepared by powder metallurgy,and the microstructure and properties were analyzed.Finally,the aluminum matrix composites with different reinforcement phases were compared.Firstly,the optimum parameters for the preparation of graphene-SiC nanoparticles were studied.The structural integrity of graphene was detected by Raman spectroscopy and the coating state was observed by scanning electron microscope(SEM).The optimum parameters were determined as follows: high energy ball milling speed 300 rpm,ball material ratio 15: 1,ball milling time 3 h,composite ratio 1:1.Then,graphene-SiC nanoparticles reinforced aluminum matrix composites were prepared by secondary ball milling,vacuum hot pressing sintering,solution aging treatment and so on.The homogeneity,microstructure and interface of the reinforced phase of the composites were analyzed by optical microscope,SEM,EDS,TEM,XRD and so on.It is found that the composite reinforcement phase is mainly distributed at the grain boundary and is closely mechanically bonded with the aluminum matrix,and there is no aluminum carbide formation at the bonding interface.The interface between graphene and coated SiC nanoparticles is very clear,and SiC nanoparticles do not form aluminum carbide with aluminum matrix.When the content of graphene and SiC nanoparticles in the composite is 0.25 wt.% and 0.50 wt.%,the composite reinforcement phase has good uniformity in the matrix.When the content is both 1.0wt.%,the composite reinforcement phase appears obvious agglomeration in the matrix.The properties of graphene-SiC nanoparticles reinforced aluminum matrix composites were evaluated by hardness test,tensile test and wear test.In terms of hardness,the hardness increases with the increase of the mass fraction of composite reinforced phase.When the content of graphene and SiC nanoparticles in the composite is 1.0wt.%,the hardness reaches the maximum.In the tensile test and wear test,the tensile and wear properties decreased with the increase of the mass fraction ofcomposite reinforced phase.When the content of graphene and SiC nanoparticles in the composite was 0.25 wt.%,The tensile and wear properties are the best.Finally,the samples of graphene-SiC nanoparticles reinforced aluminum matrix composites were compared with the aluminum matrix composites with graphene,SiC nanoparticles,graphene and SiC nanoparticles,respectively.It was found that the hardness and tensile properties of graphene-SiC nanoparticles reinforced aluminum matrix composites were lower than those of graphene and SiC nanoparticles,SiC nanoparticles.In terms of wear,graphene-SiC nanoparticles reinforced aluminum matrix composites showed good properties.