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 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, forcing molten metal under pressure 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. Additionally, there is a method comprising the steps of connecting a preform, which has been previously prepared for infiltration of molten metal, to a sprue system.

Abstract: A porous preform is placed within a permanent, nonporous, thin walled mold chamber. The mold chamber is disposed within 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. There is means for cooling the snorkel in thermal communication with the snorkel. The material is melted within the crucible. The crucible is placed in fluidic communication with the mold chamber such that the melted material seals the inside of the mold chamber from the pressure vessel to isolate a vacuum within the mold chamber.

Abstract: The apparatus for casting comprises a pressure vessel and a device for evacuating and pressurizing the vessel. The evacuating and 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 with a passage such that the melted material in the chamber can be forced down into the mold through the passage as the pressurizing device pressurize the vessel. The passage contains a filter such that the melted material is prevented from entering the interior of the mold prior to pressurization. Additionally, the apparatus is comprised of a device for heating material in the chamber and the mold such that material is melted in the chamber and stays melted as it is forced down into mold while the pressurizing device pressurizes the vessel. The heating device is disposed in the vessel.