Microstructures and properties of Fe1.25CoNi1.25CrxAl0.25 high-entropy alloys after cold-rolling and annealing

Microstructures and properties of Fe1.25CoNi1.25CrxAl0.25 (x=0.5, 0.75, 1) high-entropy alloys (HEAs) fabricated by copper mold suction casting were studied in this paper. The crystal structure of the alloy is composed of single-phase FCC solid solution, and the crystal structure does not change with the change of Cr content. The yield strength of as-cast alloys is below 200 MPa, and the elongation is above 50%. After cold-rolling and annealing, the strength and hardness of the alloy increase with the increase of Cr content. The comprehensive mechanical properties of the alloy with x=1 reach the best. The yield strength, tensile strength and elongation are 498 MPa, 770 MPa and 40%, respectively. The cubic texture of {001} 100 is the strongest texture of the specimen with x=0.5. The appropriate addition of Cr is beneficial to improve the corrosion resistance of the alloy. The alloy with x=0.75 has the best corrosion resistance in 0.5 mol/L H2SO4. The reduction of Cr content is advantageous to improve the soft magnetic properties of alloys, and Fe1.25CoCr0.5Ni1.25Al0.25 shows excellent magnetic properties. The Fe1.25CoCr0.5Ni1.25Al0.25 HEA, meanwhile, has good processability with the elongation over 50%.