Study On Preparation And Performance Of Graphene Reinforced Magnesium Matrix Composites

In recent years,the graphene is widely applied to polymer-based,ceramic-based and metal-based composites as reinforced phase for its superior physical and mechanical properties.However,the articles of study on graphene reinforced magnesium matrix composites are not many,so relevant experimental study on graphene reinforced magnesium matrix composites is designed and preceeded.Firstly,single or less layers of graphene was prepared by using advanced Hummers method,and copper-coated graphene was prepared by using chemical copper plating method.Then,graphene reinforced magnesium matrix composites were prepared by using ball mill mixing+cold pressing+hot pressed sintering craft.Metalloscope,X-ray diffraction,scanning electron microscopy and other testing methods were used to character and analyze microstructures and components of composites,and Vickers was used to test the hardness of composites.Finally,CASTEP first-principles software for calculation was used to calculate graphene-metal composite surfaces and research properties and bonding strength of different composite interfaces.When sintering temperature is up to 595℃,prepared composite surfaces are clean without crack.The interior of composites is tight which is hard to disperse.1wt.%content of graphene can encapsulate magnesium grain well.The graphene distribute in crystal boundary of composites as continuous web form.When the content of graphene is more than 1wt.%,excessive graphene is easy to produce reunite,which is harmful to microstructures and other factors of composites.The hardness of composites is up to50 HV under 1wt.% content of graphene,which is increased by 66.7% and 38.9% than that of as-cast and cold working condition of pure magnesium respectively.When mixing time is up to 12 hours,the organization homogeneity of composites can achieve maximum.It is not evident to the improvement of organization homogeneity by increasing further mixing time.The organization of composites can be defined by rolling and heat treatment.The organization homogeneity of composites can be improved when the time of heat treatment is up to 3 hours.There is a strong interaction on the interface between graphene and copper substrate.Its interfacial bonding energy is 4.79J·m-2,and the interface belong tochemical combination.The interaction between graphene and aluminium or magnesium substrates is weak.The interfacial bonding energy is 1.415J·m-2 and 0.52J·m-2,and the interface belong to physical combination.The interfacial combination in composites can be enhanced for wettability between graphene and magnesium substrates which is derived from copper plating on surface of graphene.