Patent ID: 8303869

Claim:
A method of producing a composite metal material, the method comprising: (a) mixing at least a first carbon material and a particulate metal material Z into an elastomer, and dispersing the first carbon material and the metal material Z by applying a shear force to obtain a composite elastomer, the metal material Z having a melting point lower than a melting point of the first carbon material; (b) heat-treating the composite elastomer in an atmosphere containing oxygen to vaporize the elastomer included in the composite elastomer to obtain an intermediate composite material including a second carbon material, wherein the second carbon material is derived from the first carbon material, and the metal material Z; (c) heat-treating the intermediate composite material together with a substance including an element Y having a melting point lower than the melting point of the metal material Z to vaporize the substance including the element Y; and (d) casting a composite material obtained by the step (c) in a die having a desired shape either directly or after mixing the composite material into a molten matrix metal material to obtain the composite metal material, wherein: the metal material Z is aluminum or an alloy containing aluminum as a major component; the element Y is magnesium; the heat treatment temperature in the step (b) is set at a point lower than the vaporization temperature of the substance including the element Y; the heat treatment temperature in the step (c) is set at a point higher than the heat treatment temperature in the step (b), the heat treatment temperature in the step (c) is set at a point equal to or higher than the vaporization temperature of the substance including the element Y, and the heat treatment temperature in the step (c) is set at a point lower than the vaporization temperatures of the metal material Z and the first carbon material; a surface of the first carbon material activated in the step (a) bonds to oxygen present in the atmosphere inside a furnace by the heat treatment in the step (b) to obtain the second carbon material having a surface oxidized; the composite metal material has a compressive yield strength mean value of 320 MPa or more; and the casting in the step (d) is selected from the group consisting of a metal mold casting method, a diecasting method, a low-pressure casting method, a high-pressure casting method, a thixocasting method, and a centrifugal casting method.