Abstract:
A process for preparing complex-shaped, ceramic-metal composite articles, comprising:a) contacting a non-wettable powder that is non-wetting to a metal to be used for infiltration with a shaped ceramic body to form a layer(s) of the non-wettable powder on one or more surface(s) of the shaped ceramic body wherein the shaped ceramic body has a region(s) where there is no layer of the non-wettable powder;b) infiltrating the shaped ceramic body with the metal through the region(s) where there is no layer of the non-wettable powder such that a complex-shaped ceramic-metal composite comprising one or more metal phases and one or more ceramic phases is formed, wherein the article has substantially the net shape of the shaped ceramic body and the undesirable regions of excess metal on the surface and undesirable phases within the complex-shaped ceramic-metal composite article near the surface are located only in the region(s) where there is no layer of the non-wettable powder.A complex-shaped ceramic-metal composite article with undesirable regions of excess metal and undesirable phases on the surface(s) of or within the article only where there is or was no layer of non-wettable powder.The process of the invention allows the preparation of complex-shaped ceramic-metal composite articles with undesirable regions of excess metal and undesirable phases on the surface(s) of or within the article only in the regions where there is or was no layer of non-wettable powder. The process of the invention allows the preparation of a complex-shaped ceramic-metal composite article which requires little or no machining of the surface(s) to achieve a finished article. A complex-shaped ceramic-metal composite article is prepared which contains few undesirable regions of excess metal and undesirable phases.
Abstract:
A method of coating a substrate with particles of a ceramic selected from the group consisting of diamond, carbon, graphite, and graphite or carbon-carbon composite, comprising: providing the substrate and at least one of the ceramic particles; selecting at least a carbide forming substance consisting principally of an element which is other than Ni, Cr, and Co and is capable of forming a carbide to provide a coating material; applying said coating material onto at, least one component of the substrate and the at least one ceramic particle; placing the at least one ceramic particle on the substrate; and heating the product of step (D) at a temperature sufficient to form a liquid-diffusion formed, carbide coating on the at least one ceramic particle. The ceramic particles are then coated with strong, adherent, microscopically substantially defect-free, and thermomechanically shock resistant metallized layers which are capable of practical uses over 630.degree. C.
Abstract:
Method for producing metal matrix composites. The method includes the steps of placing a substantially liquid metal in the vicinity of a reinforcement material and in the vicinity of the source of a transient magnetic field sufficient to produce an electromagnetic body force within the metal. The magnetic field is activated thereby propelling the substantially liquid metal into the reinforcement material thereby producing metal matrix composites.
Abstract:
A ground engaging tool for an earthworking machine comprises a ground engaging element with a cast-in-place metal matrix composite component. The ground engaging element comprises a metal base component and a metal matrix composite component. The metal matrix component is bonded to the metal base component. The metal matrix composite component consists of a preform having interconnecting porosity. The preform is formed from a material selected from one of ceramic, cermet, or mixtures thereof. The metal matrix composite component also consists of an infiltration metal. The preform is infiltrated by the infiltration metal and the infiltration metal is fusion bonded to the metal base component.
Abstract:
The present invention is directed to a process for fabricating ceramic-metal composites having continuous ceramic and metal phases. The process includes the steps of contacting a porous ceramic matrix material with a molten metal whereby capillary action pulls the metal into the ceramic matrix to substantially fill the void space. The present invention also provides a ceramic-metal composite having continuous metal and ceramic phases.
Abstract:
A method for fabricating ceramic-metal composites having continuous ceramic and metallic phases. In one embodiment, the metal phase includes copper metal. The method can include the steps of contacting a porous ceramic matrix material with molten metal whereby capillary action pulls the metal into the ceramic matrix to substantially fill the open void space. The present invention also provides a ceramic-metal composite having continuous metal and ceramic phases.
Abstract:
The present invention relates to the formation of a macrocomposite body by spontaneously infiltrating a permeable mass of filler material or a preform with molten matrix metal and bonding the spontaneously infiltrated material to at least one second material such as a ceramic or ceramic containing body and/or a metal or metal containing body. Particularly, an infiltration enhancer and/or infiltration enhancer precursor and/or 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. Moreover, prior to infiltration, the filler material or preform is placed into contact with at least a portion of a second material such that after infiltation of the filler material or preform, the infiltrated material is bonded to the second material, thereby forming a macrocomposite body.
Abstract:
A method of fabricating a metal matrix composite containing electrically isolated areas and the MMC formed from the method. The method comprises: (a) providing a liquid pool of unreinforced aluminum alloy; (b) infiltrating the unreinforced aluminum alloy into a stack comprising upper and lower porous preforms and an electrical insulator material placed between the preforms; (c) solidifying the liquid-phase metal to form a metal matrix composite product that completely surrounds the stack; and (d) forming at least one groove in the solidified metal, the groove extending downward to the insulating substrate so as to electrically isolate at least one region on the surface of the metal matrix composite.
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.
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. In a preferred embodiment, the gating means may comprise a porous material or a precursor to a porous material, which may optionally function as a separation facilitator. Alternatively, the separation facilitator may be provided independent of the gating means.