Self-propagating high temperature synthesis and dynamic compaction of titanium diboride/titanium carbide composites

Self-propagating High-temperature Synthesis (SHS) of titanium and boron carbide (B4C) combined with explosively driven Dynamic Compaction (DC) was employed for the fabrication of composite TiB2/TiC compacts. A 2(3) factorially designed experiment set was used to examine the effects of the TiB2/TiC ratio, delay time and C/M ratio on the consolidation and properties of the compacts. The delay time is the time between completion of the SHS reaction and compaction. The C/M ratio, the ratio of the explosive mass to that of the flyer plate, influences the pressure applied to the samples during compaction. Composites with molar TiB2/TiC ratios of 2:1 or 1:2 were prepared using Ti and B4C or Ti, C and B4C, respectively, as reactants. The SHS/DC of Ti and B4C resulted in high quality, near fully dense TiB2/TiC composite compacts. Under best conditions, the densities were greater than 98% of the theoretical maximum. While the microhardness and densities of the compacts with TiB2/TiC ratio of 2:1 were comparable to those of monolithic TiB2 and TiC, compacts with TiB2/TiC ratios of 1:2 were poorly consolidated and contained extensive cracks. Given the high energy and time efficiency, high product quality and inexpensive reactants, the SHS/DC of Ti and B4C represents an attractive technique for the economical fabrication of TiB2/TiC composites. (C) 2000 Kluwer Academic Publishers.