Microstructure and properties of bulk Al_0.5CoCrFeNi high-entropy alloy by cold rolling and subsequent annealing

Cold rolling combining subsequent annealing is implemented to tune the microstructure and mechanical properties of Al_0.5CoCrFeNi high-entropy alloy. Results show that the microstructure of Al_0.5CoCrFeNi HEA after 80% thickness reduction is severely deformed along the rolling direction. Prominent work hardening effect on Al_0.5CoCrFeNi HEAs is evidenced by the remarkable enhancement of the hardness and strength at the sacrifice of ductility. After annealing, detailed description of microstructure evolution, texture analyses as well as tensile properties are given. Strongly temperature dependent recrystallized microstructure manifests the rather high recrystallization temperature (0.81 T_m) that can be attributed to original coarse as-cast grains, severe lattice distortion effect and sluggish diffusion effect. Progressively smaller intensity of deformed texture proves the function to eliminate texture effectively of recrystallization in spite of the detection of weak recrystallization texture. Tensile tests of annealed Al_0.5CoCrFeNi HEAs show the strength decreases dramatically while ductility increases remarkably accompanying increased annealing temperature. To sum up, cold rolling combining subsequent annealing is a valid method to gain grain refined Al_0.5CoCrFeNi HEAs with adjustable properties that are prospective for many kinds of application.