Preparation And Properties Of Graphene/Aluminum Matrix And Magnesium Matrix Composites

Aluminum and magnesium matrix composite are widely used in daily life due to their low density,good corrosion resistance,high rigidity,good electrical conductivity and thermal conductivity.However,their strength and stiffness are much lower than those of steel materials,which limits their applications in structural materials.Graphene is a honeycomb two-dimensional crystal formed by sp~2 hybridization of a single layer of carbon atoms.It has high strength,high specific surface area,excellent thermal conductivity and electrical conductivity,and is an ideal metal reinforcing material.In this paper,the process of preparing graphene by shear stripping is firstly studied.The influence of shearing process on the degree of graphene peeling and its mechanism are discussed.The optimal shearing process parameters are determined,and the prepared graphene nanosheets are different.Al-1Mg-xGNP_S(x=0.1,0.3,0.5,1,2 wt.%)and Mg-1Al-xGNP_S(x=0.1,0.2,0.4wt.%)were prepared by uniform discharge doping with Al-1Mg and Mg-1Al alloy powders and pre-compression molding.Composites were systematically investigated to investigate the effect of graphene incorporation on composites and its enhancement mechanism.The main results achieved are as follows:1.Using polyvinylpyrrolidone(PVP)and surfactant sodium cholate(SC)as solvent,GNPs was successfully prepared by optimizing the shearing process parameters of the shearing machine.2.The mechanism of preparing graphene by shearing method is revealed,the adsorption of PVP and SC on the surface of graphite makes the graphite layer and the layer negatively charged,which reduces the van der Waals force between layers and the interface energy when directly interacting with water.Under the action of shearing force,the graphite layer is peeled off,and the GNPs with controlled thickness and stable existence can be obtained by controlling the shearing speed and time.3.GNPs were uniformLy dispersed in Al-1Mg and Mg-1Al mixed powders by ultrasonic assisted mechanical stirring.The dense and high strength aluminum-based and magnesium-based composites were prepared by optimizing the discharge plasma sintering process.4.Through microstructure and composition analysis,GNPs were found to be evenly distributed in the gold matrix of Al-1Mg-xGNPs and Mg-1Al-xGNPs composites.Compared with the pure Al-1Mg alloy,the tensile yield strength of the Al-1Mg-0.5%GNPs aluminum matrix composite increased from 42MPa to 77MPa,and the tensile strength increased from 88.55MPa to 162MPa,and the elongatio decreased from 3.8%to 0.3%.Compared with pure Mg-1Al alloy,the tensile yield strength of Mg-1Al-0.2%GNPS composite increased from 132MPa to 168MPa,the tensile strength increased from 142MPa to 258MPa,and the elongation decreased from 5.1%to 3.0%.5.The reinforcing effect of graphene on Al-1Mg-xGNPs aluminum matrix composites and Mg-1Al-xGNPs magnesium matrix composites is due to the uniform distribution of a certain amount of graphene in the composite matrix,which effectively prevents the dislocation of composite materials.The effect of movement and deformation is closely related to the size,morphology,distribution and addition amount of graphene.When the amount of graphene added exceeds the optimum value,the deformation resistance of the composite matrix increases sharply,resulting in a decrease in toughness of the composite.Among them,the optimum addition amount of graphene in Al-1Mg-xGNP_S and Mg-1Al-xGNP_S composite materials was 0.5%and 0.2%,respectively.