Abstract: A wear resistant metal composite which comprises formed porous fly ash obtained by forming fly ash into the desired shape and a metal impregnated into voids present in the interior of said formed fly ash, wherein the percentage by volume of said formed fly ash is 30% by volume or less, and wherein said fly ash is exposed on the surface of said wear resistant metal composite.

Abstract: A metal-based composite includes a metal matrix including aluminum as a major component, discontinuous alumina fibers buried in the metal matrix, mullite particles buried therein, and solid lubricant particles buried therein. The solid lubricant particles can be either graphite particles with a nickel layer formed on a surface thereof, or boron nitride cermet particles. By thus including the specific solid lubricant particles, the wear resistance of the metal-based composite can be improved, the wear of its mating parts can be reduced, and the friction coefficient between the metal-based composite and the mating parts can be inhibited from fluctuating. Hence, the metal-based composite can appropriately make aluminum-based internal combustion engines.

Abstract: A composite aluminum member joining process. A chemical film including potassium and fluorine is formed on an aluminum member or a flux including potassium and fluorine is coated on an aluminum member. The coated aluminum member is buried together with a disposable pattern in a predetermined assembled state in a mold including molding sand. Then, molten aluminum alloy is poured into the mold, thereby molding an aluminum alloy cast member. The mold is decompressed through the molding sand, thereby expelling tar-like substances generated when the disposable pattern comes in contact with the molten aluminum alloy, burns and vaporizes, at least from the boundary surface between the disposable pattern and the molding sand to the molding sand disposed around the disposable pattern and preventing the tar-like substances from interposing between the aluminum member and the aluminum alloy cast member made from the molten aluminum alloy.