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.