The alloy Fe - 25 m% Co - 15 m% Mo is a carbon-free iron-based alloy. It shows a high hardness combined with an enhanced thermal stability due to the precipitation of an intermetallic µ-phase (Fe,Co)7Mo6. However, below the γ↔α transformation temperature the FeCo-matrix exhibits a reversible order transition from the disordered bcc A2-lattice to the ordered B2-lattice, which deteriorates the ductility of the material. In the present study the influence of alloying elements on the B2-ordering transition in the FeCoMo system was investigated. The mechanical properties were characterized by means of impact testing and hardness measurements. The alloy design combined with well-defined heat treatments led to a significant increase in ductility, but to a decrease in hardness. Additionally, the influence of alloying elements on the aging behavior was examined. It was shown that the addition of alloying elements substantially affects the µ-phase precipitation behavior.