Research On Preparation And Properties Of Graphene Reinforced 2024 Aluminum Matrix Composites

Graphene nanosheets（GNPs）reinforced 2024 aluminum matrix composites were prepared by vacuum arc melting and hot press sintering methods,respectively,in this thesis.The effects of graphene content and rolling deformation on the mechanical properties and corrosion resistance of the composites were investigated using hardness testing,tensile property testing,intergranular corrosion and electrochemical corrosion.The micromechnism was analyzed by scanning electron microscopy（SEM）,energy spectroscopy（EDS）,and X-ray diffraction（XRD）,etc.The main conclusions are as follows.（1）The SEM morphology of the composite powder prepared by different ball milling processes shows that the lamellarization degree of the composite powder morphology is good when the ball milling time is 0.5 h and the ball-to-material ratio is10:1,and the surface of the composite powder is neat and without welding.（2）GNPs/2024Al composites are successfully prepared by vacuum arc melting method.The as-cast composites have more holes and cracks,and the material denseness and homogeneity of the composites are poor.The hardness of the 0.5 wt.%GNPs/2024Al composite is 94 HV_0.2.When the content of the graphene increases to 1.0wt.%,the pores of the as-cast tissue increase and the hardness decreases.After rolling,solution and aging treatment,the size and number of pores of the composites decrease and the hardness increases.All of the samples reach the peak aging at 12 h.（3）The GNPs/2024Al composites are successfully prepared by vacuum hot-press sintering method.The density test and metallographic analysis show that the composites have dense microstructure with no obvious pores.The hardness and tensile strength of the 0.5 wt.%GNPs/2024Al composites is the highest with 161.74 HV_0.2and 476 MPa,respectively.The plasticity and corrosion resistance of GNPs/2024Al composites decreases with the increase of graphene content.（4）The deformation amount has a strong influence on the organization and properties of GNPs/2024Al composites prepared by vacuum hot-press sintering method.After rolling,the grains in the composites are deformed along the rolling direction.With the increase of the deformation amount,the grains gradually become elongate,the hardness of the composites first increases and then decreases,and the corrosion resistance first decreases and then increases.The hardness of the composite with a rolling deformation amount of 20%is 148.9 HV_0.2,and the maximum corrosion depth is108μm at 55%of rolling deformation,and the corrosion grade is 4.