Synthesis of TiC and Ti/TiC Composites by Reaction Milling Followed by Hot Consolidation of Ti with Graphite or Heptane

Synthesis of TiC and Ti/TiC composite has been conducted by mechanical alloying and following Spark-Plasma-Sintering starting from elemental Ti powder with graphite or heptane. From graphite, formation of TiC takes place rapidly after a definite period of milling while it proceeds gradually from heptane. The apparent compositional range of Ti1−xCx is extended to a C/Ti ratio as low as 30/70 when graphite is used, while a mixture of Ti and TiC is obtained at a C/Ti ratio of 32/68 with heptane. Sintering can proceed at substantially lower temperatures compared with the conventional process, the sintering temperature decreasing with lower C/Ti ratios. The lattice parameter of TiC and the density of the compacts decrease with lower C/Ti ratios, but are larger than previously reported ones through conventional methods. The mechanism which causes the differences between graphite and heptane is discussed with respect to the reaction process during milling.