Graphene oxide colloid was prepared by the modified Hummer method.In combination with cryomilling and hot pressing sintering

graphene/7075 Al composites with 0.75%and 1%graphene content were prepared successfully.The microstructure

mechanical properties and fracture morphology of the graphene/7075 Al composites were investigated by scanning electron microscope（SEM）

vickers hardness tester and static tensile tests

respectively.The results reveal that compared with 1%graphene composite

the graphene nanocrystal of 0.75% graphene composite is completely coated with aluminum matrix

and there is no lamellar graphene agglomeration.The hardness of composites with 0.75% and1% graphene content is increased from 90 HV（no addition of graphene 7075 Al）to 125 HV and 140 HV

respectively.Both the tensile strength and elongation of the composites are increased firstly and then decreased

and the highest tensile strength value reaches 250.71 MPa and the maximum elogation value reaches 6.18%.Because the amount of graphene addition is less

the density of the composites is changed slightly.