Patent ID: 7560171

Claim:
A composite material member comprising: a main material composed of a light metal or a light metal alloy which can be molded by casting; and a secondary material joined to the main material by integrally casting with the main material, wherein a porous material is arranged on a part of a boundary area or an entire boundary area between the main material and the secondary material, wherein the light metal is aluminum or magnesium, and the light metal alloy is an alloy including at least one of aluminum and magnesium, wherein the secondary material is cast iron, iron steel, stainless steel, Fe—Cr-based alloy, Ni-based alloy, or ceramic, wherein the porous material is composed of a metal fiber or a foamed metal by which a diffusion joining can be performed with the secondary material, and wherein in the case in which the porous material has a single layer structure, the porous material is composed of a single material which has a volume rate that is from 30 to 60% when a plate thickness of a portion of the porous material which contacts the secondary material in a direction spaced from the secondary material is not less than 1 mm and less than 2 mm, and the porous material has a volume rate that is from 20 to 60% when a plate thickness of a portion of the porous material which contacts the secondary material in a direction spaced from the secondary material is not less than 2 mm, and in a case in which the porous material has a double layer structure having a first layer proximate to the secondary material and a second layer proximate to the main material, the first layer of the porous material has a plate thickness of 0.5 mm and a volume rate of 60 to 70%, and the second layer of the porous material has a plate thickness of 0.5 mm and a volume rate of 20%.