TiC is a commonly used ceramic in MMCs. This is mainly due to its high hardness and excellent bonding behavior when combined with metal binders. Depending on the production route TiC is well known to react with nickel and steel matrices thereby influencing single-phase composition and properties such as hardness. In this study the reaction of particulate TiC within a heat-treatable steel matrix produced via a solid-state powder metallurgical route was investigated. An interaction zone was found and analyzed by BSD/SEM which indicated an enrichment in molybdenum and tungsten. Based on this information a thermodynamic equilibrium model was developed to estimate the interaction zone’s composition and structure. These findings were finally compared to SAED and EDS/STEM measurements of the interaction zone giving excellent agreement between model prediction and experimental results.