Tailoring the strength and ductility of Al0.25CoCrFeNi high entropy alloy through cryo-rolling and annealing

FCC-structured Al0.25CoCrFeNi high entropy alloy (Al0.25 alloy for short) was melted and cryo-rolled. The influences of annealing temperature (800 degrees C, 1000 degrees C, 1200 degrees C) on microstructural evolution and mechanical properties were investigated. The results suggested the synchronous enhancements in strength and ductility were obtained in the cryo-rolled Al0.25 alloy annealed at 1000 degrees C with fully recrystallization and B2 phase precipitation. TEM studying on the deformation behavior of this sample revealed that a laminated HCP phase was transformed from FCC phase during the tensile deformation at ambient temperature, which served as the media of twinning. The outstanding improvements in mechanical properties benefited from the contributions of twininduced plasticity (TWIP) and phase transformation plasticity (TRIP). In addition, the order of recrystallization and the precipitation/dissolution of B2 phase for the cryo-rolled Al0.25 alloy during annealing process was tried to be clarified, which provided the guideline to tailor the mechanical properties of this alloy.

Automated summary

The study found that synchronous enhancements in strength and ductility were achieved in the cryo-rolled Al0.25 alloy annealed at 1000 degrees C, with fully recrystallization and B2 phase precipitation. The improvements in mechanical properties were attributed to the contributions of twin-induced plasticity (TWIP) and phase transformation plasticity (TRIP).