摘要:
The present invention relates to a novel process for forming metal matrix composite bodies by using a 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 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.
摘要:
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.
摘要:
The present invention relates to a novel process for forming 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 filler material or preform. Such spontaneous infiltration occurs without the application of any pressure or vacuum. 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. In yet another embodiment of the present invention, a plurality of thin tape cast preforms which are segregated by a barrier material (e.g., graphite foil) may be infiltrated with a matrix metal during a single spontaneous infiltration process.
摘要:
The present invention relates to a novel process for forming 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 filler material or preform. Such spontaneous infiltration occurs without the application of any pressure or vacuum. 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.
摘要:
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.
摘要:
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.
摘要:
Techniques to bond two or more smaller bodies or subunits to produce a unitary SiC composite structure extend the capabilities of reaction-bonded silicon carbide, for example, by making possible the fabrication of complex shapes. In a first aspect of the present invention, two or more preforms are bonded together with a binder material that imparts at least strength sufficient for handling during subsequent thermal processing. In a second aspect of the present invention, instead of providing the subunits to be bonded in the form of preforms, the subunits may be dense, SiC composite bodies, e.g., RBSC bodies. In each of the above embodiments, a preferable means for bonding two or more subunits combines aspects of adhesive and mechanical locking characteristics. One way to accomplish this objective is to incorporate a mechanical locking feature to the joining means, e.g., a “keyway” feature. The mechanical locking feature thus substitutes for, or supplements the binder qualities of the adhesive, which is especially important when the adhesive itself may be or become weak due to, for example, thermal processing.
摘要:
Composite bodies made by a silicon metal infiltration process that feature a silicon intermetallic, e.g., a metal silicide. Not only does this give the composite material engineer greater flexibility in designing or tailoring the physical properties of the resulting composite material, but the infiltrant also can be engineered compositionally to have much diminished amounts of expansion upon solidification, thereby enhancing net-shape-making capabilities. These and other consequences of engineering the metal component of composite bodies made by silicon infiltration permit the fabrication of large structures of complex shape.
摘要:
A composite body produced by a reactive infiltration process that possesses high mechanical strength, high hardness and high stiffness has applications in such diverse industries as precision equipment and ballistic armor. Specifically, the composite material features a boron carbide filler or reinforcement phase, and a silicon carbide matrix produced by the reactive infiltration of an infiltrant having a silicon component with a porous mass having a carbonaceous component. Potential deleterious reaction of the boron carbide with silicon during infiltration is suppressed by alloying or dissolving boron into the silicon prior to contact of the silicon infiltrant with the boron carbide. In a preferred embodiment of the invention related specifically to armor, good ballistic performance can be advanced by loading the porous mass or preform to be infiltrated to a high degree with one or more hard fillers such as boron carbide, and by limiting the size of the largest particles making up the mass. The instant reaction-bonded silicon carbide (RBSC) composite bodies surpass previous RBSC's as armor materials, and in this capacity approach the ballistic performance of current carbide armor ceramics but with potentially lower cost manufacturing methods, e.g., infiltration techniques.
摘要:
Improved silicon carbide composites made by an infiltration process feature a metal phase in addition to any residual silicon phase. Not only are properties such as mechanical toughness improved, but the infiltrant can be so engineered as to have much diminished amounts of expansion upon solidification, thereby enhancing net-shape-making capabilities. Further, multi-component infiltrant materials may have a lower liquidus temperature than pure silicon, thereby providing the practitioner greater control over the infiltration process. In particular, the infiltration may be conducted at the lower temperatures, where low-cost but effective bedding or barrier materials can terminate the infiltration process once the infiltrant has migrated through the permeable mass up to the boundary between the mass and the bedding material.