Abstract: Embodiments of the present invention provide composite bodies having a discontinuous graphite preform and at least one silicon-bearing metal alloy infiltrant. Embodiments of the present invention also provide methods for producing such composite bodies. The metal alloy is preferably comprised of aluminum, copper, or magnesium, or combinations thereof. Certain preferred embodiments provide at least one aluminum alloy having from about 5% silicon to about 30% silicon, more preferably from about 11% to about 13% silicon, as an alloying element. Certain presently preferred embodiments provide an aluminum-silicon eutectic composition having about 12.5% silicon. Embodiments of the invention provide composite materials be “tuned” to more closely match thermal expansion characteristics of a number of semiconductor or integrated circuit materials such as, but not limited to, silicon, alumina, aluminum nitride, gallium nitride, and gallium arsenide while also providing high thermal conductivity.

Abstract: The invention relates to a method that involves (a) removing graphite from at least one surface of a metal graphite composite material; (b) chemically cleaning or plasma etching the surface of the metal graphite composite material; (c) applying a metal-containing material to the surface of the chemically cleaned or plasma etched metal graphite composite material, and thereby forming an intermediate layer; (d) applying a metal coating on the intermediate layer, and thereby forming a composite material. The invention also relates to a composite material comprising (a) a metal graphite composite substrate having at least one surface that is substantially free of graphite; (b) a metal-containing intermediate layer located on a surface of the substrate; and (c) a metal coating on the intermediate layer.

Abstract: A heat sink including a composite material base plate that defines at least one through hole. At least one composite material insert is position into the at least one through hole prior to pressure infiltration. The composite material insert is oriented to increase thermal conductivity in the through-plan direction.

Abstract: Embodiments of the present invention provide composite bodies having a discontinuous graphite preform and at least one silicon-bearing metal alloy infiltrant. Embodiments of the present invention also provide methods for producing such composite bodies. The metal alloy is preferably comprised of aluminum, copper, or magnesium, or combinations thereof. Certain preferred embodiments provide at least one aluminum alloy having from about 5% silicon to about 30% silicon, more preferably from about 11% to about 13% silicon, as an alloying element. Certain presently preferred embodiments provide an aluminum-silicon eutectic composition having about 12.5% silicon. Embodiments of the invention provide composite materials be “tuned” to more closely match thermal expansion characteristics of a number of semiconductor or integrated circuit materials such as, but not limited to, silicon, alumina, aluminum nitride, gallium nitride, and gallium arsenide while also providing high thermal conductivity.

Abstract: The invention relates to a method that involves (a) removing graphite from at least one surface of a metal graphite composite material; (b) chemically cleaning or plasma etching the surface of the metal graphite composite material; (c) applying a metal-containing material to the surface of the chemically cleaned or plasma etched metal graphite composite material, and thereby forming an intermediate layer; (d) applying a metal coating on the intermediate layer, and thereby forming a composite material. The invention also relates to a composite material comprising (a) a metal graphite composite substrate having at least one surface that is substantially free of graphite; (b) a metal-containing intermediate layer located on a surface of the substrate; and (c) a metal coating on the intermediate layer.

Abstract: The invention relates to a method that involves (a) removing graphite from at least one surface of a metal graphite composite material; (b) chemically cleaning or plasma etching the surface of the metal graphite composite material; (c) applying a metal-containing material to the surface of the chemically cleaned or plasma etched metal graphite composite material, and thereby forming an intermediate layer; (d) applying a metal coating on the intermediate layer, and thereby forming a composite material. The invention also relates to a composite material comprising (a) a metal graphite composite substrate having at least one surface that is substantially free of graphite; (b) a metal-containing intermediate layer located on a surface of the substrate; and (c) a metal coating on the intermediate layer.

Abstract: A process for manufacturing a soluble casting core for use in casting complex shaped metal matrix composite components. The soluble casting core is generated by a sequence of steps which provide a molten slurry mixture composed of an alkali metal salt such as sodium carbonate and a plurality of ceramic particulates such as magnesium oxide dispersed therein. After heating and mixing the slurry mixture is solidified in a mold pattern to form a casting core configured to generate a complex shaped component during a casting process. The soluble casting core is used for casting molten metal alloys therein, without failure of the casting surfaces and forming of a complex shaped metal matrix composite component. The soluble casting core is readily dissolved and separated from the soluble casting core by immersing the core mold in heated water and/or exposing to steam, without damage to the metal matrix composite component.

Abstract: A process for manufacturing a soluble casting core for use in casting complex shaped metal matrix composite components. The soluble casting core is generated by a sequence of steps which provide a molten slurry mixture composed of an alkali metal salt such as sodium carbonate and a plurality of ceramic particulates such as magnesium oxide dispersed therein. After heating and mixing the slurry mixture is solidified in a mold pattern to form a casting core configured to generate a complex shaped component during a casting process. The soluble casting core is used for casting molten metal alloys therein, without failure of the casting surfaces and forming of a complex shaped metal matrix composite component. The soluble casting core is readily dissolved and separated from the soluble casting core by immersing the core mold in heated water and/or exposing to steam, without damage to the metal matrix composite component.

Abstract: The invention relates to a method that involves (a) removing graphite from at least one surface of a metal graphite composite material; (b) chemically cleaning or plasma etching the surface of the metal graphite composite material; (c) applying a metal-containing material to the surface of the chemically cleaned or plasma etched metal graphite composite material, and thereby forming an intermediate layer; (d) applying a metal coating on the intermediate layer, and thereby forming a composite material. The invention also relates to a composite material comprising (a) a metal graphite composite substrate having at least one surface that is substantially free of graphite; (b) a metal-containing intermediate layer located on a surface of the substrate; and (c) a metal coating on the intermediate layer.

Abstract: A spray deposition apparatus comprises a source of aqueous fiber slurry that includes a mixture of milled graphite fibers in suspension. A slurry input of the spray deposition apparatus is coupled to the source of aqueous fiber slurry. The slurry input receives the mixture of aqueous fiber slurry. A gas pressure input receives pressurized gas. A nozzle aspirates the mixture of aqueous fiber slurry with the pressurized gas to produce a stream of fiber cluster droplets.

Abstract: Methods and materials for preparing investment molds useful in pressure infiltration casting of near net-shape metal or metal matrix composite (MMC) components. One embodiment of the invention includes disposing a slurry of an appropriately sized refractory material and a vehicle around a preform or fugitive pattern, removing the bulk of the vehicle, then curing/drying the refractory material to create an investment mold of the invention. Subsequently, pressure infiltration casting with a molten infiltrant using the investment mold permits infiltration of the mold cavity and/or preform without infiltration of the investment mold. As a result, the investment mold readily is removed to provide the near net-shape metal or MMC component. In other embodiments of the invention, a non-fugitive pattern is used, typically with a modified refractory cement of the invention.

Abstract: Disclosed are methods and materials for preparing metal matrix composite (MMC) components that have low weight, good thermal conductivity and a controllable in-plane coefficient of thermal expansion. One embodiment of the invention features a metal matrix composite that includes a metal alloy and random in-plane discontinuous fibers. In some embodiments, the metal alloy includes aluminum, copper or magnesium. In certain embodiments, the metal matrix composite includes additives that enable solution hardening. In other embodiments, the metal matrix composite includes additives that enable precipitation hardening. Another embodiment of the invention features a method of manufacturing a metal matrix composite. The method includes contacting random in-plane discontinuous fibers with a binder, and pressurizing the random in-plane discontinuous fibers and the binder to form a bound preform. The preform is pressurized to a pressure greater than the molten metal capillary breakthrough pressure of the bound preform.

Abstract: Disclosed are methods and materials for preparing metal matrix composite (MMC) components that have low weight, good thermal conductivity and a controllable in-plane coefficient of thermal expansion. One embodiment of the invention features a metal matrix composite that includes a metal alloy and random in-plane discontinuous fibers. In some embodiments, the metal alloy includes aluminum, copper or magnesium. In certain embodiments, the metal matrix composite includes additives that enable solution hardening. In other embodiments, the metal matrix composite includes additives that enable precipitation hardening. Another embodiment of the invention features a method of manufacturing a metal matrix composite. The method includes contacting random in-plane discontinuous fibers with a binder, and pressurizing the random in-plane discontinuous fibers and the binder to form a bound preform. The preform is pressurized to a pressure greater than the molten metal capillary breakthrough pressure of the bound preform.

Abstract: Disclosed are economical methods and apparatus for high throughput pressure infiltration casting. Methods of the invention use a mold vessel as an evacuation chamber along with an evacuation cap to produce superior quality near-net shape finished cast parts with low porosity. Other methods of the invention use an improved heat transfer technique for directionally solidifying molten infiltrant at an increased rate to increase further the throughput of the pressure infiltration casting cycle. The invention also provides apparatus for practicing methods for high throughput pressure infiltration casting. One embodiment of an apparatus of the invention is a removable evacuation cap, often used in conjunction with a fill tube. Another apparatus embodiment is an evacuation cap coupled to a mold vessel which is used as an evacuation chamber.

Abstract: A method of high throughput pressure casting involving the steps of providing a mold vessel containing an infiltrant and a mold cavity; evacuating the mold cavity, and heating the infiltrant to form a molten infiltrant which isolates a reduced pressure in the mold cavity; transferring the mold vessel containing the molten infiltrant to a pressure vessel; applying pressure to the molten infiltrant to move it into the mold cavity; and cooling the molten infiltrant in the mold cavity to solidify the molten infiltrant. The mold cavity may contain a preform to produce a metal matrix composite.

Abstract: A mold cavity in a mold vessel is evacuated. A charge of molten infiltrant is transported into the mold vessel while the vacuum is maintained in the mold cavity. Pressure is applied to the molten infiltrant to move the molten infiltrant from the mold vessel into the mold cavity. The molten infiltrant is cooled in the mold cavity to solidify the infiltrant. A fill tube can be used to transport the infiltrant to the mold vessel.

Abstract: A mold vessel having a mold cavity is heated and evacuated. A charge of molten infiltrant is provided into the mold vessel from a source not in vacuum communication with the mold vessel while a reduced pressure is maintained in the mold cavity. Pressure is applied to the molten infiltrant to move it into the mold cavity. The molten infiltrant in the mold cavity is cooled to solidify the molten infiltrant. The mold cavity may contain a preform to produce a metal matrix composite.

Abstract: The invention provides methods for producing semi-permanent casting tooling, as well as semi-permanent casting tooling apparatus. Casting tooling including a blend of high char resin and refractory powder; casting tooling prepared from a blend of sol-gel ceramic precursor and refractory powder; and a preform including a leachable core as well as methods for their production are provided. The casting tooling of the invention can be used in casting processes including die casting, permanent mold casting and pressure infiltration casting. Also provided is an investment mold casting technique compatible with a pressure infiltration process.

Abstract: A method for producing semi-permanent casting tooling, including the steps of blending a high char resin with a refractory powder to form a plastic moldable material; shaping the plastic moldable material to form a green tooling body; and heating the green tooling body to convert the high char resin into carbon char to form reusable casting tooling. The casting tooling can be used in casting processes including die casting, permanent mold casting and pressure infiltration casting.

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, allowing for rapid finished article throughput. An apparatus for pressure infiltration casting is also provided.