<p>This study investigates the effects of the addition of C and Ti on the microstructure and mechanical properties of CrMnFeCoNi high-entropy alloy. As-cast CrMnFeCoNi alloys with and without C/Ti exhibit a face-centered cubic (FCC) single-phase microstructure with coarse grains and elemental segregation. The addition of C and Ti reduces the secondary dendrite arm spacing in the as-cast alloy. The as-cast CrMnFeCoNi alloy contains Mn or Mn/Cr oxide inclusions, whereas the C/Ti-added alloy contains Ti oxide inclusions. The addition of C and Ti induced the formation of TiC precipitates during solidification, thereby increasing the hardness of the as-cast alloy. Annealing the C/Ti-added alloy at 800&#xa0;°C resulted in the formation of Cr₂₃C₆ and TiC precipitates at various locations such as grain boundaries, inclusion interfaces, and the FCC matrix. Crystallographic analysis shows that rectangular Cr₂₃C₆ precipitates with {220} facets exhibit a cube-on-cube orientation relationship (OR) with the FCC matrix. The plate-shaped TiC precipitates on {200} habit planes exhibit specific ORs with coherent and semicoherent interfaces in the FCC matrix. The hardness and compressive yield strength of the C/Ti-added alloy improved significantly after annealing, which is primarily due to the precipitation strengthening of the plate-shaped TiC precipitates.</p> Graphical Abstract <p></p>