Combustion synthesis and subsequent Explosive Densification of Titanium Carbide Ceramics

Abstract

Explosive densification following combustion synthesis of titanium and graphite powder mixtures has been used to fabricate bulk compacts (100-mm diameter × 20-mm thick) of TiC ceramics. A model rocket ignitor was used to initiate the combustion reaction in ≈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 thet _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.