Abstract: A cast composite material is formed from about 5 to about 35 volume percent of particulate reinforcement, preferably silicon carbide particles, embedded in an aluminum alloy matrix having from about 8.5 to about 12.6, most preferably about 9.5 to about 11.0, weight percent silicon. The cast composite material is particularly well suited for use as a foundry alloy for remelting purposes. Other alloying elements may be added without interfering with the beneficial effects of the silicon.

Abstract: The invention discloses an improved method for forming metal matrix composite castings. The method achieves the casting having increased mechanical properties by using a selectively permeable mold in conjunction with pressurized gas. This allows a greater degree of metal infiltration within the interstices of a suspended preform. The method teaches the use of whiskered, fibered and particulated ceramic constituents for use in the preform, as well as various embodiments of casting methods.

Abstract: There is disclosed methods for the manufacture of a metal matrix composite having a metal or metal alloy matrix and a uniform dispersion of a second phase. The second phase is either a refractory metal or a nonmetal. An element which reacts with both the matrix and the second phase is added to increase the loathing density of the second phase and to improve adhesion between the components of the composite. When the metal alloy matrix is copper or a copper based alloy, suitable reactive elements include zirconium, titanium, chromium and mixtures thereof.

Abstract: The invention produces a light metal alloy composite having a nickel coated graphite or carbon with a nickel-containing intermetallic phase within a portion of a casting. A mold is provided to cast a light metal into a predetermined shape. A nickel coated carbon phase structure is placed into a portion of the mold. The light metal is cast into the mold around the carbon structure to wet an interface between the light metal and the nickel coated carbon structure. A nickel-containing intermetallic phase is formed in the light metal proximate the nickel coated carbon to provide increased wear resistance. The light metal is then solidified to form the metal matrix composite.

Abstract: A method for impregnating a metal product with a hard wear-resistant surface area comprises providing a wear-resistant layer in the form of a sintered sheet having a pattern which facilitates metallurgical bonding with a metal melt and optionally, at least one "pin" integrally attached onto a surface of the sheet. This wear-resistant layer is attached onto the sand core and a metal melt is cast so as to produce the final product. This method can be used to produce a variety of metal products although cast iron is preferred. Moreover, this process can effectively employ any of the hard phases which can be sintered, e.g., tungsten carbide, chromium carbide, and the like.

Abstract: Composite casting process for making castings, consisting in particular of light metal alloys reinforced by fiber or foamed material inserts, in particular motor parts such as pistons, cylinders, cylinder heads and motor blocks of internal combustion engines. In this process, firstly, a preform reinforced by the fiber or foamed material inserts is made by embedding and the penetration of a fiber bundle or a foamed material body in molten matrix metal or by a molten matrix metal and subsequently solidifying it. Then, the preform is immersed in a molten metal bath and subsequently inserted into a casting mould for integrally casting or casting around the final casting.

Abstract: The present invention relates to a novel method for forming metal matrix composite bodies. Particularly, a permeable mass of filler material is formed into a preform. An infiltration enhancer or an infiltration enhancer precursor or an infiltrating atmosphere are also in communication with the preform, at least at some point during the process, which permits molten matrix metal to spontaneously infiltrate the preform when the preform is placed into the molten matrix metal. A means for maintaining the preform at least partially below the surface of the molten matrix metal can also be utilized. In a preferred embodiment a reservoir may be employed to supply a second metal which has a different composition from the first source of matrix metal.

Abstract: Sintered ceramic preforms for metal matrix composites fabricated by a method comprising: (a) preparing a homogeneous mixture containing appropriate amounts of silicon-containing fibers/particulates, such as silicon carbide, at least one solvent, at least one polymer, and an oxide-containing material, such as boric acid or phosphoric acid, capable of forming a low melting silicate with a silicon oxide, such as a borosilicate; (b) shaping a green ceramic preform from the mixture, such as by injection molding; (c) removing the solvent(s) and the polymer(s); (d) oxidizing the surfaces of the silicon-containing fibers to form a layer of the silicon oxide thereon; (e) heating the preform to a temperature sufficient to react the oxide-containing material with the silicon oxide to form the low melting silicate material; (f) liquid phase sintering the fibers in the presence of liquid silicate material to strengthen the preform; and (g) cooling the sintered preform to ambient.

Abstract: A process for producing a preform having a buffer layer for use in compositing a metal matrix composite where the buffer layer is provided at a boundary between a composited portion and a non-composited portion of a metallic material in the metal matrix composite. The process includes subjecting a first dispersion including a liquid medium and a ceramic whisker homogeneously dispersed in the liquid medium to filtration under pressure to form a primary processed preform having a volume fraction of 12 to 30%, depositing on the primary processed preform a second dispersion including a liquid medium and, homogeneously dispersed therein, a binder and at least one member selected from the group consisting of a short fiber and a ceramic whisker, and drying the primary processed preform to form a buffer layer having a volume fraction lower than the volume fraction of the primary processed preform and in a range from 2 to 10%.

Abstract: The present invention relates to a novel process for forming metal matrix composite bodies. Specifically, in a particularly preferred embodiment for making metal matrix composite bodies by a spontaneous infiltration technique, an infiltration enhancer or an infiltration enhancer precursor 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 riigidized preform. A structural refractory material which holds the preform is made by forming a first precursor to the supportive structural refractory material and subsequently causing the precursor to become a rigid supportive structural member. Such spontaneous infiltration occurs without the requirement for the application of any pressure or vacuum.

Abstract: The apparatus for casting comprises a pressure vessel and a device for pressurizing the vessel. The pressurizing device is in fluidic connection with the vessel. The apparatus is also comprised of a chamber disposed in the pressure vessel within which material is melted. There is a mold adapted to contain a preform disposed in the vessel and in fluidic connection with the chamber by a passage such that melted material in the chamber can be forced down into the mold through the passage as the pressurizing device pressurizes the vessel. A heating device is disposed in the vessel. There is also a device for directionally solidifying the material in the mold. Additionally, there is a method comprising the steps of loading the pressure vessel by disposing a material within the chamber whereby the material is in fluidic connection with the mold adapted to contain a preform through the passage. The passage has a filter disposed therein.

Abstract: A porous body is formed and joined to the component by sintering a metal powder to the component. The porous body and component are placed into a piston casting die. Molten metal is poured into the die such that the porous body becomes infiltrated with the molten metal and the molten metal is allowed to solidify. The porous body may be formed by sintering loose metal powder to the component, or by forming a separate body by die pressing of metal powder and which body may be subsequently sintered and joined to the component.

Abstract: The present invention pertains to a system for casting a melted material. The system has a mold having a mold cavity for forming the melted material. There is a coating disposed about the mold cavity which chemically reacts with the melted material such that the melted material cannot react with mold. In this manner, the cast part can be more easily released from the mold, since it cannot chemically react with it. The present invention is also a method of casting a melted material. The method comprises the step of coating a mold cavity of a mold with a material which is chemically reactive with the melted material. Next, there is the step of introducing melted material into the mold cavity such that melted material infiltrates and chemically reacts with the material on the mold to form a composite skin which prevents the melted material from chemically reacting with the mold. Then, there can be the step of cooling the melted material.

Abstract: A moldable dental composition for use in forming or repairing dental restorations composed of a mixture of high- and low-fusing temperature metal particles and a volatile binder, composed substantially or entirely of wax, with the binder having a concentration of between thirty (30%) to eighty percent (80%) by volume of the mixture. The average particle size of the high-fusing metal particles are above one micron, and preferably between four microns and eighty microns in size. The composition is heat treated at a temperature to melt the low-fusing temperature metal particles and to eliminate the binder, leaving a porous metal structure with a void volume above thirty percent (30%). The voids are filled using a filler material of metal or ceramic.

Abstract: A fiber-organic composition includes from about 5% to 50% by volume of uniformly dispersed, non-planar or three dimensionally random oriented inorganic fibers or whiskers, and a thermoplastic material such as paraffin wax. The composition also includes surfactants to promote wetting and dispersion of the inorganic fibers or whiskers. These materials are subjected to high shear mixing to form a uniform randomly oriented three-dimensional dispersion of the inorganic fibers or whiskers. After molding the mixture in such a manner so as not to disrupt the uniform, three-dimensional orientation of the fibers or whiskers, a majority of the thermoplastic material is removed leaving a shaped body or preform having sufficient strength for handling. The shaped body or preform can then be infiltrated with molten metal or the like to form a metal matrix composite.

Abstract: A metal composite material provides improved strength at all temperatures, in particular at those temperatures greater half the melting point of its matrix. The metal composite material is at least 50 volume percent hard particulate material in a matrix which is significantly more ductile than the hard particulate material. At or above 50 volume percent hard particulate material, each particle is surrounded by a thin film of the matrix material. This thin film resists deformation by converting sliding motion between particles into the rotational motion of the particles about each other. The matrix may be made by infiltrating a powder of the particulate material with a charge of the matrix material, for example, by hot isostatically pressing the matrix material into the powder or by melting a block of matrix material on top of the powder and thus infiltrating the powder by gravitational flow of the melted matrix material into the powder.

Abstract: A composite material comprises a body, e.g., a slab, of a fused refractory oxycompound (3) having a multiplicity of discrete inclusions such as lumps (1) of an aluminum-wettable RHM in its surface. These bodies are especially useful as aluminum-wettable but non-current carrying components of aluminum reduction cells.

Abstract: The present invention pertains to an apparatus for casting which includes a melt chamber within which a metal is disposed. The melt chamber includes means for melting the material. A mold chamber is disposed beneath the melt chamber comprised of a mold defining a mold cavity within which the metal is formed and a preform is disposed. There is also a riser cavity fluidically connected to the mold cavity for holding a charge of melted metal. There is also provided means for fluidically connecting the melt chamber to the mold chamber and a valve element for controlling the flow of metal through the connecting means such that when the connecting means is opened, the chambers are fluidically connected and when the connecting means is closed, the chambers are fluidically isolated. The mold chamber has means for evacuating the mold chamber and means for pressurizing the mold chamber such that the melted metal disposed within the riser cavity is forced into the preform.

Abstract: For silicizing porous moldings of silicon carbide/carbon, a mixture of silicon carbide powder, organic binder and, if appropriate, carbon is molded to give a green compact, the binder of the green compact is removed by carbonization at about 1000.degree. C. in a non-oxidizing atmosphere and the resulting blank is silicized by the action of molten silicon, while the resulting blank rests on a porous SiSiC carrier, whose lower part is in contact with the molten silicon. The carrier used may be a close packing of porous SiSiC rings which are arranged mutually parallel and perpendicularly on a graphite firing plate which is charged with silicon and is impermeable to molten silicon; or the carrier may be plane having a plurality of recess; or the carrier may have a straight channel with an angular cross section and recesses, into which the blank to be silicized is placed, wherein the SiSiC carrier has downward protruding side walls, whose undersides are in contact with the molten silicon.

Abstract: A method for pressure infiltration casting is provided wherein steps of preheating and evacuating a mold cavity and infiltrant charge are carried out in a separate vessel from a pressure vessel wherein the mold cavity is filled using a vent tube, allowing for rapid finished article throughput.

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 pertains to a method of forming a metal matrix composite. The method comprises the steps of surrounding at least one insert with reinforcement material. Next, there is the step of orienting the insert and reinforcement within a mold. Then, there is the step of infiltrating the mold with liquid metal such that the reinforcement material around the insert is infiltrated. In a preferred embodiment, the insert comprises a hollow core and closed ends and the surrounding step includes the step of wrapping reinforcement around the insert. Preferably, the hollow core is exposed and the insert is leached out with the appropriate leaching solution.

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: A method of making a composite material consists of entraining finely divided solid additive particles in a stream of ionized inert gas and ionizing the inert gas and utilizing heat generated by the ionized gas to heat the solid particles to a high temperature which is less than the temperature in at which the solid particles become non-solid due to melting sublimination or dissociation. Then, injecting the stream of gas and entrained heated solid particles into a molten metal mass to provide a mixture of finely divided solid particles and molten metal and thereafter causing physical agitation of the mixture of molten metal and solid particles to establish a substantially uniform distribution of solid particles in the molten metal. Such physical agitation of molten metal is continued until the mixture of finely divided particles and metals is completely solidified.

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: The present invention is a method for casting and densification. The method is comprised of the steps of filling a mold in a pressure vessel to a predetermined level with molten metal and then increasing the pressure in the vessel such that voids formed within the metal are substantially closed without removing the mold with the metal from the pressure vessel. Preferably, after the increasing pressure step, there is the step of cooling the molten metal to ambient temperatures. In one embodiment, the increasing pressure step includes the step of increasing pressure in the vessel at a predetermined rate through the liquidus, liquidus/solidus and solidus phases of the metal. Alternatively, the increasing pressure step can include the step of increasing pressure at a predetermined rate through the liquidus/solidus and solidus phase of the metal. Alternatively, the increasing pressure step can include the step of increasing pressure at a predetermined rate through the solidus phase of the metal.

Abstract: A method for impregnating a metal product with a hard wear-resistant surface layer comprises providing a wear-resistant layer in the form of a partially sintered sheet having at least one peg formed therein; attaching the wear-resistant layer to a mold surface; and casting a metal melt so as to produce a metal product having a wear-resistant material surface layer. Preferably the mold surface is a sand core and the sheet has a hexagonal pattern molded therein so as to form a plurality of pegs.

Abstract: A composite material mixture of free flowing reinforcement particles in a molten metal is solidified at a cooling rate greater than about 15.degree. C. per second between the liquidus and solidus temperatures of the matrix alloy. This high cooling rate imparts a homogeneous structure to the solid composite material. Care is taken to avoid the introduction of gas bubbles into the molten composite material while the mixture is stirred to prevent segregation of the particles. For viscous melts, an artificial surface layer such as a fiberglass blanket may be used to prevent entrapment of bubbles during pre-casting stirring. Additionally, gas bubbles are removed from the molten mixture by filtering and skimming.

Abstract: A method for forming a metal matrix composite within a mold of investment material. The method comprises the steps of forming a preform mixture of liquid flow medium, binding agent and reinforcement into the desired shape of a metal matrix composite. Then, allowing the preform mixture to solidify into desired shape. Next, encasing the preform mixture within a container of investment material. Then, heating the preform mixture at a controlled rate which first allows any fluid, such as water, to evaporate, then allows removal of the flow medium. Next, sintering the remaining reinforcement material and binder to form a solid preform. Then, disposing molten metal on top of the solid preform within the container such that the molten metal forms a seal with the container. Next, pressurizing the molten metal such that it is forced into said preform. Next, solidifying the molten metal to form a metal matrix composite in the shape of this preform; and removing the investment material from metal matrix composite.

Abstract: A porous preform is placed in a nonporous mold chamber of a pressure vessel. A material is placed in a crucible of the pressure vessel. The pressure vessel is evacuated through a snorkel fluidically connected to the mold chamber and extending therefrom out of the pressure vessel. The material in the crucible is melted. The crucible is placed in fluidic communication with the mold chamber such that the melted material fluidically seals the inside of the mold chamber and the snorkel from the interior of the pressure vessel to fluidically isolate the mold chamber from the interior of the pressure vessel so that a pressure differential exists therebetween.

Abstract: A method for impregnating a metal product with a hard wear-resistant surface area comprises providing a wear-resistant layer in the form of a sintered sheet having at least one "pin" integrally attached onto a surface of the sheet. This wear-resistant layer is attached onto the sand core and a metal melt is cast so as to produce the final product. This method can be used to produce a variety of metal products although cast iron, and in particular, ductile iron are preferred. Moreover, this process can effectively employ any of the hard phases which can be sintered, e.g., tungsten carbide, chromium carbide, and the like. Preferably, both the sheet and the "pins" are made from the same mixture of a wear-resistant material, an organic binder, and at least one plasticizer.

Abstract: The present invention relates to a novel method for forming a metal matrix composite body. Particularly, a permeable mass of filler material is formed into a preform, the preform having at least a portion thereof which contains a cavity. An infiltration enhancer and/or an infiltration enhancer precursor and/or an infiltrating atmosphere are also in communication with the preform, at least at some point during the process, which permits molten matrix metal to spontaneously infiltrate the preform when the preform is placed into molten matrix metal. An infiltrating atmosphere is provided in communication with the cavity in the preform for at least a portion of the process, and molten matrix metal is contacted with an exterior portion of the preform, such that molten matrix metal will spontaneously infiltrate the preform from an exterior surface thereof toward the cavity. The process can be performed in a continual manner.

Abstract: The process according to the invention involves using an infiltration technique with a binder metal 16 in a layer filled with grains of melted tungsten carbide 15, the layer being arranged between the walls of a mould 13 and a core 2, the walls of the mould being made of foundry sand bonded by resins. The invention makes it possible to reduce the cost of the infiltration process.

Abstract: Metal matrix composites are manufactured in a vacuum die casting machine. Solid aggregate material, at least 65 volume percent, is placed in a die, the die is evacuated and heated, and molten metal is driven by a piston to infiltrate the solid aggregate material where it subsequently solidifies to form a metal matrix composite.

Abstract: A method of forming a metallic composite product having a specific gravity no greater than 1.8 and a thermal expansion no greater than 16.times.10.sup.-6 .degree. C. in a preheated mold. The portion of the mold between a cavity and the gate has a stainless steel wire gauge for retaining particles. The mold is filled with screened fly ash, glass, hollow spheres having a particle size in the range of 50 to 200 micrometers and a globularness of at least 90%, which has been preheated to the same temperature as the mold. Molten aluminum alloy is injected into the mold at a pressure in the range of from 40 to 80 kgf cm.sup.2 at the gate and at a flow velocity in the range of 0.08 to 0.20 m/second.

Abstract: The present invention is a process for forming net shape parts by matching mold and component CTE and having the mold heated near the liquidus such that the mold and the component go through the same thermal and dimensional changes during cool down of the component. The present invention also pertains to a method of producing the matched CTE mold. The method includes the step of providing the first material in porous form. Next, there is the step of melting the second material. Then, there is the step of infiltrating the first porous material with the second melted material in proportion such that their combined CTE essentially matches that of the composite component. The composite mold and composite component can be formed at the same time. In an alternative method for forming the mold having a specific CTE, there is the step of providing the first material and the second material.

Abstract: In the production of cast fittings by the precision casting process of the casting-on technique, primary and secondary pieces can be easily separated from one another if the primary piece surface is isolated with a ceramic interlayer being chemically not attackable by the constituents of the alloys used. An interlayer containing zirconium dioxide is especially preferred.

Abstract: Engine block cylinder liners are formed from high melting temperature aluminum alloy composites. A cast composite is first formed from a high melting temperature aluminum alloy, e.g. Al-Mn, Al-Cr, Al-Ni, Al-Fe or Al-Cr-Zr, and refractory particles, e.g. alumina. This composite is then extruded into a tubular sleeve. If desired, a long tube may be extruded which is then cut into desired lengths. These new cylinder liners have the following desirable properties: high melting temperature, good strength at the service temperature, higher thermal conductivity than cast iron, good wear resistance and good corrosion resistance.

Abstract: An apparatus and process is disclosed for the preparation by molding of composite materials formed of a metallic or organic matrix and at least one reinforcing element which includes a mold having an axis of revolution, the mold being equipped with a rotator allowing it to rotate about its axis, with a device for feeding liquid matrix material and with a device for feeding a reinforcing element. The reinforcing element feeding device opens into the feed device of the matrix material-feeding device which causes turbulence. The feed device can be a shoot, a casting channel, a feed pipe, a funnel or another equivalent device.

Abstract: A process for producing composite materials with a metal matrix and with a content of powder reinforcer agent lower than is minimum theoretical compaction value, with said process being based on an infiltration technique, is disclosed, which essentially consists in charging the reinforcer material to a casting mould, and then infiltrating into the same mould the metal matrix in the molten state, with said metal matrix being let cool until it solidifies, and characterized in that the reinforcer agent, consisting of non-metal powders, is blended, before being charged to said casting mould, with a diluting agent having a different compaction degree, constituted by metal fibres and/or ceramic fibres and/or ceramic whiskers and/or metal powders of the same composition as of the matrix.

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 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. Such spontaneous infiltration occurs without the requirement for the application of any pressure or vacuum.

Abstract: The present invention relates to a novel process for forming macrocomposite bodies. Particularly, a suitable matrix metal, typically in a molten state, is in contact with a suitable mass of filler material or preform located adjacent to, or in contact with, at least one second material in the presence of a suitable reactive atmosphere in an impermeable container, at least at some point during the process, which permits a reaction to occur between the reactive atmosphere and the molten matrix metal and/or mass of filler material or preform and/or impermeable container, thereby causing molten matrix metal to infiltrate the mass of filler material or preform due to, at least in part, the creation of a self-generated vacuum. The impermeable container being sealed by a molten glassy material. Such self-generated vacuum infiltration occurs without the application of any external pressure or vacuum.

Abstract: A method for preparing a composite material comprises the steps of providing a first mixture of a molten aluminum-base matrix alloy having at least about 4 percent by weight magnesium, and a mass of discontinuous reinforcing particles that are not soluble in the molten matrix alloy, and mixing the first mixture to wet the matrix alloy to the particles and to distribute the particles throughout the volume of the molten matrix alloy. The first matrix alloy is diluted to reduce the magnesium content of the mixture to less than about 4 percent by weight magnesium, to produce a second mixture, and the second mixture is cast. The second mixture has at least about 5 volume percent particles, and preferably has about 5-25 volume percent particles.

Abstract: The present invention relates to alloys having substantially uniform aggregate distribution, a method of making such alloys, and centrifugally cast members made from such alloys. The alloys of the present invention utilize aggregates of tungsten carbide, vanadium carbide and titanium carbide so formulated to allow them to be uniformly distributed throughout the alloy matrix.

Abstract: The present invention relates to the use of a gating means in combination with a spontaneous infiltration process to produce a metal matrix composite body. Particularly, a permeable mass of filler material or a preform is spontaneously infiltrated by molten matrix metal to form a metal matrix composite body. A gating means is provided which controls or limits the areal contact between molten matrix metal and the filler material or preform. The use of a gating means provides for control of the amount of matrix metal which can contact the preform or filler material, which may result in less machining of a formed metal matrix composite body compared with a similar metal matrix composite body made without a gating mean. Moreover, the use of a gating means ameliorates the tendency of a formed metal matrix composite body to warp due to the contact between the formed composite body and matrix metal carcass.

Abstract: The present invention relates to forming a metal matrix composite between at least two bodies having a similar or a different chemical composition, the metal matrix composite functioning as a bonding means which bond to or fixes the bodies together. Particularly, a metal matrix composite is produced by a spontaneous infiltration technique by providing a filler material or preform with an infiltration enhancer and/or an infiltration enhancer precursor and/or and infiltrating atmosphere, which are in communication with the filler material or preform at least at some point during the process. Molten matrix metal then spontaneously infiltrates the filler material or preform, whereby the metal matrix composite serves to bond together two or more bodies.

Abstract: A squeeze-casting method is taught for manufacturing metal matrix composites which require little or no finishing operations. This method utilizes a combination of techniques, fundamentals of which are found in the investment casting, die casting and metal matrix composite-making arts. The method comprises, forming a wax pattern around the preform and investing the pattern to form a melt-impermeable shell-mold around it. The shell-mold is dewaxed leaving the preform positioned within it. The shell-mold is heated before it is placed in a die cavity of a conventional die caster for high pressure injection of molten metal. Molten metal is poured into the die cavity and pressurized with sufficient pressure and for long enough to impregnate the preform. The metal encapsulates the shell-mold which allows for equilibrated pressures within said die. The pressure is released and the shell-mold is removed from the die cavity before the molten metal in the shell-mold solidifies.

Abstract: A method of casting metal matrix composites wherein there is a wide disparity in the respective densities of the metal matrix and the reinforcing particles. The particles are added to a melt of molten metal and the mixture is stirred using an impeller rotating at a high speed so as to ensure an even distribution of the less dense reinforcing particles throughout the denser metal matrix.

Abstract: The present invention relates to a novel method for forming metal matrix composite bodies. A permeable mass of filler material is spontaneously infiltrated by a molten matrix metal. Particularly, an infiltration enhancer and/or an infiltration enhancer precursor and/or an infiltration atmosphere are in communication with the filler material, at least at some point during the process, which permits molten matrix metal to spontaneously infiltrate the filler material. After infiltration has been completed to a desired extent, additional matrix metal is added to that matrix metal which has spontaneously infiltrated the filler material to result in a suspension of filler material and matrix metal, said suspension having a lower volume fraction of filler relative to matrix metal. The matrix metal then can be permitted to cool in situ or the mixture of matrix metal and filler material can be poured into a second container as a casting process to form a desired shape which corresponds to the second container.