Strengthening the CoCrFeNiNb0.25 high entropy alloy by FCC precipitate

High entropy alloys (HEAs) are facing difficulties in balancing strength and ductility, and till now there is no satisfactory solution. In this paper, the CoCrFeNiNb0.25 HEA with good ductility was strengthened by a face centered cubic (FCC) precipitate after annealing heat treatment. When the CoCrFeNiNb0.25 HEA was annealed at 750 °C, a lath-shaped FCC precipitates with nano basket-weave microstructures appeared and distributed randomly in the proeutectic FCC phase. Due to the precipitation strengthening, the yield stress of the CoCrFeNiNb0.25 HEA almost doubled but its ductility was just slightly damaged.