Abstract:
A method of manufacturing ceramic matrix composite objects is disclosed. The method comprises the steps of providing first and second substantially two dimensional arrangements of one or more fibre plies, and machining the first and second arrangements to predetermined configurations to form first and second preforms. The second preform is made to conform to a surface of the first preform such that at least some of the fibres of the second preform are orientated at least partially in a plane outside that defined by the fibres of the first preform, and fixed to the first preform to form a combined first and second preform. The combined first and second preform is rigidised. Ceramic matrix composite objects manufactured by this method are also disclosed.
Abstract:
We provide a method for the in situ development of graphene containing silicon carbide (SiC) matrix ceramic composites, and more particularly to the in situ graphene growth within the bulk ceramic through a single-step approach during SiC ceramics densification using an electric current activated/assisted sintering (ECAS) technique. This approach allows processing dense, robust, highly electrical conducting and well dispersed nanocomposites having a percolated graphene network, eliminating the handling of potentially hazardous nanostructures. Graphene/SiC components could be used in technological applications under strong demanding conditions where good electrical, thermal, mechanical and/or tribological properties are required, such as micro and nanoelectromechanical systems (MEMS and NEMS), sensors, actuators, heat exchangers, breaks, components for engines, armours, cutting tools, microturbines or microrotors.
Abstract:
Composite bodies made by a silicon metal infiltration process that feature a silicon intermetallic, e.g., a metal suicide. 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:
Elément de blindage antibalistique, comprenant un corps céramique constitué dans un matériau comprenant, en pourcentage volumique, entre 35% et 55% de carbure de silicium, entre 20% et 50% de carbure de bore, entre 15% et 35% d'une phase de silicium ou d'une phase comprenant du silicium.
Abstract:
A boron carbide composite body produced by an infiltration process that possesses high mechanical strength, high hardness and high stiffness has applications in such diverse industries as precision equipment and ballistic armor. In one embodiment, 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 reactable carbonaceous component. In an alternate embodiment, the infiltration can be caused to occur in the absence of the reactable carbonaceous component, e.g., to produce "siliconized boron carbide". Potential deleterious reaction of the boron carbide with silicon during infiltration is suppressed by alloying or dissolving a source of boron, or a source of carbon, or preferably both boron and carbon 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 morphological features, particularly the ceramic phases, making up the composite body. The instant reaction-bonded boron carbide (RBBC) composite bodies are at least comparable in ballistic performance to current boron carbide armor ceramics but feature lower cost and higher volume manufacturing methods, e.g., infiltration techniques.