| Currently,the powder sintering route is the mainstream method for preparing aluminum/graphene composite materials.However,this method has major shortcomings,that is,it is difficult to mass produce aluminum/graphene composite materials,which restricts its large-scale application.For this reason,this project proposes a method for preparing aluminum/graphene composites by a liquid phase powder mixing and smelting process.This method overcomes the problem that the powder route cannot mass produce aluminum/graphene composites.In this paper,reduced graphene oxide powder,nano aluminum powder and copper powder are used as raw materials to study the influence of the liquid phase mixing process on the dispersibility of graphene;then the uniformly dispersed graphene powder is introduced into the aluminum melt to prepare aluminum/ Graphene composite materials,this article applies extrusion and drawing deformation processing to the composite material to obtain aluminum/graphene composite material wire,discusses the structure evolution behavior of the composite material during the deformation process,and analyzes the mechanical and electrical properties of the composite wire material.The liquid phase ultrasonic dispersion process was used to mix graphene and nano aluminum powder in anhydrous ethanol environment.The effect of ultrasonic time and graphene content on the dispersion of graphene in the mixed powder was studied,and the graphene content was found to be 5wt.%,and the ultrasonic time is more than 6h,a unique "sandwich" structure of mixed powder can be obtained,in which nano aluminum powder wraps the graphene nanosheets;similar results are also found in the nano copper powder and graphene mixed powder structure.A smelting process is used to prepare a multi-component aluminum/graphene composite material(graphene content 0～0.04%).In the as-cast state,graphene is uniformly distributed at the grain boundary of the aluminum matrix.As the content of graphene increases,the aluminum grains The size shows a decreasing trend.When the graphene content is 0.04%,the aluminum grain size is about 40μm.The aluminum grains are elongated after extrusion deformation and cold drawing,and the composite material presents a fibrous structure.The wire is annealed at 320℃/2h After treatment,the composite material transforms into an equiaxed structure,and the aluminum grain size is about 18 μm.The drawn composite wire has a very high tensile strength(more than 300MPa),but at the expense of plasticity;after annealing,the plasticity of the composite wire is significantly increased,exceeding 22%,and the strength is reduced.Graphene The increase in the content and the decrease in the wire diameter contribute to the improvement of the tensile strength of the composite material.After replacing aluminum powder with nano-copper powder,the composite material showed similar microstructure evolution characteristics.Compared with the aluminum/graphene composite material under the same conditions,the tensile strength of the composite material containing 2% Cu was improved,and the plasticity change was not much.The annealed composites all have microporous aggregate fracture.The electrical performance test of aluminum/graphene composite wire found that with the increase of graphene content,the electrical conductivity of the composite material increased first and then decreased.After annealing,the electrical conductivity of the composite material increased significantly,with an average increase of 2.5%IACS.When the graphene content is 0.02 wt.%,the electrical conductivity of the composite wire after annealing reaches 63.78%IACS,and the wire diameter increases,which is not conducive to the improvement of the electrical conductivity of the composite.Similar rules are found in copper-containing aluminum/graphene composite materials,but compared to aluminum/graphene composite materials,the conductivity of Cu-containing composite materials is reduced.At 0.02 wt.% graphene,the conductivity of the composite material is 60.54% IACS. |
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