Abstract: 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.

Abstract: A siliconized boron carbide composite material is made by infiltrating molten silicon metal into a porous mass including boron carbide. The porous mass contains little or no reactable carbon. The infiltration is designed and intended such that the infiltrant is substantially non-reactive with the constituents of the porous mass. The composite body so formed contains boron carbide and silicon metal, but substantially no silicon carbide formed in-situ from a reaction of the silicon metal with a carbon source. Such siliconized boron carbide composite materials have utility in armor applications.

Abstract: A diamond-reinforced SiC ceramic composite material and shaped article. The addition of diamond to the microstructure greatly enhances properties such as hardness and Young's modulus. Such a composite material has considerable promise as an armor material. In particular, significant increases in ballistic performance can be achieved versus a non-diamond-containing composite, particularly versus the M993 threat. Reaction bonded silicon carbide (RBSC) ceramics with 7% diamond were shown to offer ballistic performance levels that matched the best commercial ceramics tested on the program.

Abstract: 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.

Abstract: Current top performing SAPI systems are B4C-containing (hot pressed B4C or reaction bonded B4C). These systems will not function well versus future WC/Co threats due to the inability of B4C to withstand high pressure impacts. New approaches will be needed for next generation SAPI ceramics. Three related concepts are disclosed herein, each of which will lead to improved reaction bonded ceramics for next generation SAPI applications. The first concept aims to reactively heat treat reaction bonded B4C, causing. SiC and SiB6 to form at the expense of B4C. The second approach will add Ti to the system, thus allowing TiC and TiB2 to form at the expense of B4C. Finally, the third concept will evaluate the use of finer particle sizes, thus improving the static properties of the ceramics (with the aim of enhancing multi-hit performance). In all cases, preliminary work has been conducted to demonstrate the viability of the concepts. This will lead to a new family of advanced armor ceramics.

Abstract: Composite bodies made by a silicon metal infiltration process that feature a metal phase in addition to any residual silicon phase. 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. Certain liquid-based preforming techniques are particularly well suited to the task, particularly where a high volumetric loading of the reinforcement component is desired.

Abstract: 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.

Abstract: 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 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.

Abstract: 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.

Abstract: Silicon infiltration technology, e.g., siliconizing or reaction-bonding, is used to produce ceramic-rich composite bodies having utility as ballistic armor. In the main embodiment of the invention, the ballistic armor includes a reaction-bonded silicon carbide body (RBSC). 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, and by limiting the size of the morphological features making up the composite body. This control of “grain size” can be accomplished by controlling the size of the largest particles making up the porous mass to be infiltrated, but also of importance is controlling the processing conditions, particularly by controlling the factors that cause grain growth, coarsening of microstructure, and/or grain coalescence.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: Silicon infiltration technology is used to produce ceramic bodies having utility as ballistic armor. In a first aspect of the invention, the ballistic armor includes a reaction-bonded silicon carbide body (RBSC). Good ballistic performance can be advanced by loading the permeable mass or preform to be infiltrated to a high degree with one or more hard fillers, and by limiting the size of the largest particles making up the mass. In a second aspect, the silicon infiltration technology, e.g., siliconizing or reaction-bonding, is used to bond silicon carbide fibers to at least the back surface of a ceramic armor body, thereby enhancing ballistic stopping power. A third aspect of the invention pertains to the ability to engineer RBSC bodies such that there is little dimensional change during processing, thereby permitting high dimensional reproducibility in large-scale production.

Abstract: 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.

Abstract: Silicon infiltration technology is used to produce ceramic bodies having utility as ballistic armor. In a first aspect of the invention, the ballistic armor includes a reaction-bonded silicon carbide body (RBSC). Good ballistic performance can be advanced by loading the permeable mass or preform to be infiltrated to a high degree with one or more hard fillers, and by limiting the size of the largest particles making up the mass. In a second aspect, the silicon infiltration technology, e.g., siliconizing or reaction-bonding, is used to bond silicon carbide fibers to at least the back surface of a ceramic armor body, thereby enhancing ballistic stopping power. A third aspect of the invention pertains to the ability to engineer RBSC bodies such that there is little dimensional change during processing, thereby permitting high dimensional reproducibility in large-scale production.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.