FeCrMnNiCx (x = 0.1, 0.3, 0.5 and 1) bulk alloys were synthesised by Vacuum Arc Smelting. The alloy with 2 at. % of carbon (x = 0.1) is a single-phase and uniform material with no element or phase segregation. The alloys with higher carbon content were two phase materials. The equiatomic FeCrMnNiC alloy with two phases had the best corrosion resistance in 3.5% NaCl solution at room temperature under atmospheric pressure. Ion irradiation of FeCrMnNiC0.1 with FCC structure by 600 KeV Xe+2 to 50 displacements per atom (dpa) at 623 K revealed the alloy high radiation hardness by the absence of phase transformation and elemental segregation. The single-phase FeCrMnNiC0.1 alloy has a hardness of 7.5 ± 0.84 GPa and reduced Young's modulus of 250 ± 28.1 GPa.