Encouraged by experimental reports of diamond precipitation in carbon-containing materials under warm dense matter conditions and in shock compression experiments, we examine the behavior of carbon in TiC using density functional theory–molecular dynamics simulations. Two polymorphs of TiC are considered, the ambient-pressure $B1$ ($Fm\overline{3}m$) structure in which C-C interactions are prevented by geometric constraints and a high-pressure $Cmcm$ structure in which C atoms condense into zigzag chains. Chemistry-inspired bonding analyses confirm the covalently bound nature of these chains and further illuminate important interatomic interactions in both structures. Upon melting of $B1$ TiC, new short-range C-C interactions develop in the liquid, while the preexisting C-C interactions in $Cmcm$ TiC persist in the liquid. The resulting carbon networks in the melt provide a promising environment for eventual diamond nucleation.

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• Chemical bonding
• High-pressure studies
• Phase transitions
• Carbon-based materials
• Ab initio molecular dynamics