COMBUSTION SYNTHESIS AND SUBSEQUENT EXPLOSIVE DENSIFICATION OF TITANIUM CARBIDE CERAMICS

Explosive densification following combustion synthesis of titanium and graphite powder mixtures has been used to fabricate bulk compacts (100-mm diameter X 20-mm thick) of TiC ceramics. A model rocket ignitor was used to initiate the combustion reaction in almost-equal-to 65 pct dense green pressed reactants of titanium and carbon powder mixtures. Upon completion of reaction, the reacted mass was allowed to cool. After the desired time delay (t(d)) and while the reacted mass was still above the ductile-brittle transition temperature, an explosive charge was detonated in contact with a steel driver plate to transmit the pressure into the reacted mass and consolidate it to solid density. Temperature-time cooling profiles for the reacted material were developed using calculations based on a heat flow model. The explosive loading conditions, namely, the densification pressure controlled by the ratio of explosive charge mass (C) to driver plate mass (M) ratio (C/M) and the t(d) between the combustion reaction completion and explosive detonation, were observed to critically affect the density and the microstructure of the final compacted reaction product.