Fabrication Of Copper Nanoparticles Modified Graphene Reinforced Aluminum Matrix Composites And Their Properties

Aluminum matrix composites have broad application prospects due to their good machinability,corrosion resistance,wear resistance and light weight.Graphene has attracted extensive attention of researchers because of its super-high mechanical properties and unique physicochemical properties,especially its extremely high tensile strength and Young’s modulus,becoming an ideal reinforcement for aluminum matrix composites.At present,there are many problems in graphene reinforced aluminum matrix composites,such as poor quality of graphene,difficulty in dispersion in aluminum matrix,weak interfacial bonding between graphene and matrix,etc.Therefore,how to explore new technological ideas to obtain graphene reinforced aluminum matrix composites with excellent comprehensive properties is a difficult problem at present.In this paper,graphene/aluminum composites with uniform dispersion,complete structure and good interfacial bonding with aluminum matrix were successfully prepared by in situ chemical vapor deposition combined with powder metallurgy.Firstly,high quality graphene nanosheets(Cu-NPs@GN)with uniform loading of copper nanoparticles were prepared by salt template method combined with in-situ chemical vapor deposition.On this basis,the reinforcement was uniformly dispersed in the aluminum matrix by intermittent ball milling.Finally,graphene reinforced aluminum matrix bulk composites were prepared by cold-press sintering and hot extrusion.The effects of precursor solution ratio and in-situ chemical vapor deposition process parameters on the preparation of graphene were systematically studied;the interface reaction between reinforcement and aluminum matrix was investigated;the effects of powder metallurgy parameters and graphene content on the microstructure and mechanical properties of bulk composites were investigated;.strengthening mechanism of graphene reinforced aluminum matrix composites was systematically discussedThe results show that the ratio of precursor solution and in-situ chemical vapor deposition temperature have an important influence on the preparation of Cu-NPs@GN reinforcement.Optimizing process parameters can improve the quality of graphene while achieving uniform load of copper particles.Intermittent ball milling avoids cold welding compared with continuous high-energy ball milling,achieving uniform reinforcement dispersion as well as protecting the structure of graphene to the greatest extent;copper particles can improve the situation of non-wetting between aluminium and carbon,thus forming a solid interface between graphene and aluminum,making graphene play a better role in load transfer and ensuring the strengthening efficiency of graphene;Compared with graphene modified by ex-situ method,the copper particles anchored on in-situ Cu-NPs@GN are not easy to fall off during the forming process,and the strengthening effect is more obvious.Load transfer mechanism,grain refinement and Orowan dislocation strengthening are the main strengthening mechanisms of Cu-NPs@GN/Al composites.Through systematic research and calculation,it is found that load transfer mechanism dominates the strengthening effect.