In-situ underwater-shock consolidation of combustion synthesized titanium carbide

摘要

Densification fo TiC produced by self-propagating high temperature synthesis was performed by in-situ underwater-shock consolidation. Titanium and activated carbon powders were used as raw materials, which were mixed from 0.6 to 1.0 in C/Ti molar ratio. Combustion velocity was accelerated with increasing quantity of the carbon powder. The velocity at the composition of C/Ti=0.6 and 1.0 was approximately 2.3 and 8.5 mm/s, respectively. Shock pressure was estimated to be above 4 GPa in teh assembly used by ion gap method. Density and micro Vickers hardness of the TiC compacts were increased as increase of C/Ti ratio, and their maximum values were 4.72 Mg/m~3 and 32 GPa at C/Ti=1.0, respectively. The change of electron diffraction pattern such as diffuse scattering with the deflection from stoichiometry exhibited the same tendency as the sintered product. This fact shows that SHS and subsequent shock consolidation processes used was well-controlled. Fracture surface of the compact consists of mainly intergranular and partly transgranular or cleavage fractures. It was confirmed by TEM observations that sufficient interparticle bonding and densification were achieved by the present process.