Composite material and method of producing the same, and composite metal material and method of producing the same

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;
• (d) grinding a composite material obtained by the step (c) to powder, the composite material including a carbon-based material and the metal material Z;
• and
• (e) causing a molten matrix metal material to permeate the composite 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;
• a material for the matrix metal material is the same as a material for the metal material Z;
• and
• the composite metal material has a compressive yield strength mean value of 320 MPa or more.