Fine tuning of tensile properties in CrCoNi medium entropy alloy through cold rolling and annealing

Abstract

In the present study, tensile properties of CrCoNi medium entropy alloy with different microstructures (recovery, partial recrystallization, recrystallization) were investigated by subjecting cold-rolled samples to different annealing conditions. The microstructure of the cold-rolled sample showed the presence of severely deformed grains with several deformation twins. Annealing of the cold-rolled samples at 700 degrees C and above for 60 min led to fully recrystallized microstructure, while annealing at temperatures lower than 700 degrees C led to recovery and partially recrystallized microstructures. The annealed samples showed a typical strength-ductility trade-off with an increasing fraction of recrystallized grains and increasing average grain size in samples with partially recrystallized and fully recrystallized microstructure, respectively. Fine tuning of microstructure led to a remarkable combination of strength (similar to 1 GPa) and uniform elongation (28%) in the sample with partially recrystallized microstructure, which consists of similar to 77% of recrystallized grains with an average recrystallized grain size of similar to 3 mu m.