The feasibility of engineering bimodal grain size distributions to achieve superior mechanical properties was explored in two face-centered cubic compositionally complex alloys, namely CrMnFeCoNi and its high-performance subvariant CrCoNi. Therefore both alloys were processed down to the nanocrystalline grain size regime by utilizing high-pressure torsion and subsequently annealed at intermediate temperatures. Especially the CrCoNi alloy is prone to formation of bimodal microstructures and for an annealing treatment at 500 °C for 100 h an excellent combination of ultra-high tensile strength, exceeding 1500 MPa, and decent ductility with elongations to failure of 10% could be achieved.
