this invention relates generally to a novel method of manufacturing a composite body , such as a zrb 2 -- zrc -- zr composite body , by utilizing a post - treatment process and to the novel products made thereby . more particularly , the invention relates to a method of modifying a composite body comprising one or more boron - containing compounds which has been made by the reactive infiltration of a molten parent metal into a bed or mass containing boron carbide , and optionally one or more inert fillers , to form the body .