Composite metal material and preparation method and application thereof

The invention discloses a composite metal material and a preparation method and application thereof, and belongs to the technical field of metal preparation. The preparation method of the composite metal material comprises the following steps that under the low-temperature condition, graphene oxide is dispersed in water, and a graphene oxide solution is obtained after uniform dispersion; the preparation method comprises the following steps: sequentially adding nickel sulfate hexahydrate, potassium persulfate and potassium hydroxide into a graphene oxide solution at normal temperature, stirring, filtering, washing and drying to obtain nickel hydroxide/graphene oxide; magnesium alloy powder is added into an ethanol solution to obtain a magnesium alloy solution, nickel hydroxide/graphene oxide is added into the magnesium alloy solution, and composite magnesium alloy powder is obtained through stirring, filtering and drying; and after heat preservation treatment is conducted on the composite magnesium alloy powde