▎ 摘　　要

NOVELTY - An alumina-coated graphene comprises an alumina coating layer having thickness of 2-5 nm. USE - Alumina-coated graphene is used for preparing graphene-reinforced aluminum alloy composite material (all claimed). ADVANTAGE - The alumina-coated graphene improves interfacial properties between graphene nanomaterial and aluminum alloy substrate. The agglomeration of graphene is effectively prevented by coating alumina on the surface of graphene. DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for the following: (1) preparation of alumina-coated graphene, which involves uniformly mixing aluminum salt, hexamethylenetetramine and surfactant (S), heating obtained mixed reaction solution, obtaining uniform transparent alumina gel, adding graphene oxide to deionized water, ultrasonically dispersing, adding an alkaline substance, obtaining an alkaline graphene oxide dispersion, adding the alkaline graphene oxide dispersion to the alumina gel, heating under ultrasonic stirring, centrifuging the reaction product, washing and drying. The content ratio of aluminum salt, hexamethylenetetramine and surfactant (S) is 0.005-1 mol:1 mol:0.5-1 g; (2) graphene-reinforced aluminum alloy composite material, which comprises an aluminum alloy matrix, and a nano-reinforced phase distributed in the aluminum alloy matrix. The nano-reinforced phase is alumina-coated graphene; and (3) preparation of graphene-reinforced aluminum alloy composite material, which involves adding alumina-coated graphene to a solvent, ultrasonically dispersing, adding aluminum alloy powder, uniformly stirring, ultrasonically dispersing, washing, drying, obtaining a mixed powder, adding the mixed powder into a stirring ball mill filled with liquid nitrogen, starting the ball mill when the liquid nitrogen immerses all the milling balls, uniformly mixing, adding obtained powder into a feeding device of a laser selective melting device, evacuating molding cavity, introducing argon gas, transferring the mixed powder to the substrate of the molding cavity, processing single layer, molding, and quenching the molded sample.