Abstract: The present invention relates to a novel process for forming metal matrix composite bodies by using a reactive barrier material. Particularly, an infiltration enhancer or an infiltration enhancer precursor or an infiltrating atmosphere are in communication with a filler material or a preform, at least at some point during the process, which permits molten matrix metal to spontaneously infiltrate the filler material or preform up to the reactive barrier material. Such spontaneous infiltration occurs without the requirement for the application of any pressure or vacuum. Accordingly, shaped metal matrix composite bodies can be produced having superior surface finish.

Abstract: The present invention relates to the formation of a metal matrix composite body by a spontaneous infiltration technique. Particularly, an infiltration enhancer or infiltration enhancer precursor can be positioned at least partially between or at an interface between a matrix metal and a filler material (or preform) which is to be infiltrated by molten matrix metal. Moreover, at least at some point during the process, an infiltrating atmosphere may be in communication with the filler material or preform or matrix metal.

Abstract: This invention broadly relates to methods for producing self-supporting silicon carbide and silicon carbide composite bodies. More particularly, this invention relates to silicon carbide and silicon carbide composites, grown by the oxidation reaction of a silicon metal with a gas comprising at least one gas selected from the group consisting of fluorinated hydrocarbon gases, chlorohydrocarbon gases, and chlorofluorocarbon gases.

Abstract: Novel self-supporting ceramic structures are produced by the oxidation reaction of a molten metal precursor with a vapor-phase oxidant to form an oxidation reaction product. The resulting ceramic material of the polycrystalline oxidation reaction product consists essentially of an oxidation reaction product and, optionally, one or more non-oxidized constituents of the metal precursor.

Abstract: There is disclosed a method for making a self-supporting ceramic composite article having a porous core bearing a dense surface layer formed integrally with said core. A preform comprises a filler material and parent metal distributed therethrough, wherein the volume percent of parent metal is sufficient to form a volume of oxidation reaction product exceeding the total volume available within said preform. The parent metal is melted and reacted with an oxidant to form an oxidation reaction product filling the spatial volume and leaving voids. The reaction is continued to further transport molten parent metal through the oxidation reaction product to at least one surface of the preform to form oxidation reaction product on said surface substantially free of voids thereby forming a relatively dense surface layer.

Abstract: A metal matrix composite is formed by contacting a molten matrix metal with a permeable mass of filler material or preform in the presence of an infiltrating atmosphere. Under these conditions, the molten matrix metal will spontaneously infiltrate the permeable mass of filler material or preform under normal atmospheric pressures. Once a desired amount of spontaneous infiltration has been achieved, or during the spontaneous infiltration step, the matrix metal which has infiltrated the permeable mass of filler material or preform is directionally solidified. The directionally solidified metal matrix composite may be heated to a temperature in excess of the liquidus temperature of the matrix metal and quenched. This technique allows the production of spontaneously infiltrated metal matrix composites having improved microstructures and properties.

Abstract: The present invention relates to modifying the properties of a metal matrix composite body by a post formation process modification treatment. The post formation process treatment may be applicable to a variety of metal matrix composite bodies produced by various techniques, and is particularly applicable to modifying the properties of a metal matrix composite body produced by a spontaneous infiltration technique. Particularly, at least a portion of the matrix metal of the metal matrix composite body and/or the filler material of the metal matrix composite body is modified or altered after the formation process. Preferably, the preform contains a second non-metal material, an infiltration enhancer of infiltration enhancer precursor, and an infiltration atmosphere.

Abstract: This invention relates generally to a novel method of preparing self-supporting bodies, and novel products made thereby. In its more specific aspects, this invention relates to a method for producing self-supporting bodies comprising one or more boron-containing compounds, e.g., a boride or a boride and a carbide, by reactive infiltration of molten parent metal into a preform comprising boron carbide or a boron donor material combined with a carbon donor material and, optionally, one or more inert fillers, to form the body. Specifically, a boron carbide material or combination of a boron donor material and a carbon donor material, and in either case, optionally, one or more inert fillers, are sedimentation cast, slip cast or pressed onto or into a body and into a particular desired shape.

Abstract: This invention relates generally to a novel method of manufacturing a composite body, such as a ZrB.sub.2 -ZrC-Zr (optional) composite body, by utilizing a post-treatment process and to the novel products made thereby. More particularly, the invention relates to a method of modifying a composite body comprising one or more boron-containing compounds (e.g., a boride or a boride and a carbide) which has been made by the reactive infiltration of a molten parent metal into a bed or mass containing boron carbide, and optionally one or more inert fillers, to form the body.

Abstract: The present invention relates to a novel process for forming metal matrix composite bodies. Particularly, an infiltration enhancer and/or an infiltration enhancer precursor and/or an infiltrating atmosphere are in communication with a rigidized filler material or a rigidized preform, at least at some point during the process, which permits molten matrix metal to spontaneously infiltrate the rigidized filler material or rigidized preform. Such spontaneous infiltration occurs without the requirement for the application of any pressure or vacuum.

Abstract: The present invention relates to novel ceramic-filled metal matrix composites and methods for making the same. Particularly, a permeable mass of filler material is spontaneously infiltrated by, for example, an aluminum alloy, in the presence of nitrogen-containing atmosphere. A reservoir feeding technique for forming metal matrix composite bodies is also disclosed. The reservoir feeding technique can also be used to form complex (e.g., a metal bonded to a metal matrix composite) metal matrix composite bodies.

Abstract: Ceramic foams in which the open cells are connected by a three-dimensional, substantially continuous ceramic matrix formed of interconnected hollow ligaments, are made from an open-cell, reticulated precursor metal, i.e. a metal foam. The precursor metal first is treated so as to allow a support coating to form thereon, and thereafter the coated precursor is heated above the melting point of the metal in the presence of an oxidant to form an oxidation reaction product.

Abstract: Self-supporting bodies are produced by reactive infiltration of a parent metal into a boron carbide material which may contain one or both of a boron donor material and a carbon donor material. The reactive infiltration typically results in a composite comprising a boron-containing compound, a carbon-containing compound and residual metal, if desired. The mass to be infiltrated may contain one or more inert fillers admixed with the boron carbide material, boron-containing compound and/or carbon-containing compound. The relative amounts of reactants and process conditions may be altered or controlled to yield a body containing varying volume percents of ceramic, metal, ratios of one ceramic to another and porosity.

Abstract: Self-supporting bodies are produced by reactive infiltration of a parent metal into a boron nitride material typically resulting in a body comprising a boron-containing compound, a nitrogen-containing compound and metal. The mass to be infiltrated may contain one or more inert fillers admixed with the boron nitride, to produce a composite by reactive infiltration, which composite comprises a matrix which embeds the filler material. The matrix, in a composite body containing filler material, comprises one or more of metal, a boron-containing compound and a nitrogen-containing compound. The relative amounts of reactants and process conditions may be altered or controlled to yield a body containing varying volume percents of ceramic, metal and/or porosity. The mass to be infiltrated can be contained within a refractory vessel having a venting means included therein.

Abstract: The present invention relates to a novel method for forming metal matrix composite bodies and novel products produced by the method. Particularly, a permeable mass of filler material or a preform is provided which has included therein at least two different matrix metal powders. Moreover, an infiltration enhancer and/or an infiltration enhancer precursor and/or an infiltrating atmosphere are in communication with the filler material or preform, at least at some point during the process, which permits molten matrix metal, upon contact with the filler material or preform, to spontaneously infiltrate the filler material or preform. The presence of powdered matrix metal in the preform or filler material reduces the relative volume fraction of filler material to matrix metal.

Abstract: This invention relates generally to a novel method of preparing self-supporting bodies, and to novel products made thereby. In its more specific aspects, this invention relates to a method of producing self-supporting bodies comprising one or more boron-containing compounds, e.g., a boride or a boride and a carbide, by reactive infiltration of a molten parent metal actinide into (1) a bed or mass containing boron carbide and, optionally, (2) at least one of a boron donor material (i.e., a boron-containing material) and a carbon donor material (i.e., a carbon-containing material), (3) a bed or mass comprising a mixture of a boron donor material and a carbon donor material and, optionally, (4) one or more inert fillers in any of the above masses, to form the body.

Abstract: The present invention relates to a novel process for forming a plurality of thin metal matrix composite bodies. Particularly, an infiltration enhancer and/or an infiltrating atmosphere are in communication with a filler material or preform, at least at some point during the process, which permits molten matrix metal to spontaneously infiltrate the plurality of filler materials or preforms. Such spontaneous infiltration occurs without the application of any pressure or vacuum and occurs in a single step. In an embodiment of the present invention, the filler material may be sprayed upon a thin sheet of matrix metal. Alternatively, the filler material may be shaped via tape casting, slip casting, etc. to provide a thin preform. In another embodiment of the present invention, a body of matrix metal may be coated with a filler material such that upon spontaneous infiltration a metal matrix composite body is produced which inversely replicates the configuration of the original body of matrix metal.

Abstract: A net shaped ceramic-reinforced aluminum matrix composite is formed by forming a permeable mass of ceramic material with a defined surface boundary having a barrier, and contacting a molten aluminum-magnesium alloy with the permeable mass of ceramic material in the presence of a gas comprising from about 10 to 100% nitrogen, by volume, balance nonoxidizing gas, e.g. hydrogen or argon. Under these conditions, the molten alloy spontaneously infiltrates the ceramic mass under normal atmospheric pressures until it reaches the barrier. A solid body of the alloy can be placed adjacent to a permeable bedding of ceramic material having a barrier, and brought to the molten state, preferably to at least about 700.degree. C., in order to form the net shape aluminum matrix composite by infiltration. In addition to magnesium, auxiliary alloying elements may be employed with aluminum. The resulting composite products may contain a discontinuous aluminum nitride phase in the aluminum matrix.

Abstract: This invention relates generally to a novel directed metal oxidation process which is utilized to produce self-supporting bodies. In some of the more specific aspects of the invention, a parent metal (e.g., a parent metal vapor) is induced to react with at least one solid oxidant-containing material to result in the directed growth of a reaction product which is formed from a reaction between the parent metal and the solid oxidant-containing material. The inventive process can be utilized to form bodies having substantially homogeneous compositions, graded compositions, and macrocomposite bodies.

Abstract: A method of producing a self-supporting ceramic composite body having therein at least one cavity which inversely replicates the geometry of a positive mold of parent metal. The method includes embedding the mold of parent metal within a conformable bed of filler to provide therein a cavity shaped and filled by the mold. The assembly is heated to melt the parent metal mold, e.g., an aluminum parent metal mold, and contacted with an oxidant to oxidize the molten parent metal to form a polycrystalline material which grows through the surrounding bed of filler, the molten metal being drawn through the growing polycrystalline material to be oxidized at the interface between the oxidant and previously formed oxidation reaction product whereby the cavity formerly filled by the mold of parent metal is eventually evacuated of the metal. There remains behind a cavity whose shape inversely replicates the original shape of the mold.