Microstructure and texture evolution during annealing of equiatomic CoCrFeMnNi high-entropy alloy

Abstract

• Recrystallization texture in high entropy alloys is reported for the first time. • The texture is compared to other low SFE alloys e.g. TWIP and austenitic steels. • Great resistance to grain coarsening during recrystallization. • Retention of deformation texture components during annealing like TWIP steels. • Stronger S than Brass and Goss components unlike TWIP and austenitic steels. Evolution of microstructure and texture after heavy cold rolling and subsequent annealing in a wide temperature range was first studied in an FCC equiatomic CoCrFeMnNi high-entropy alloy (HEA). Development of a submicron-cell structure and a strong brass-type texture was observed after 90% cold rolling. An ultrafine microstructure having average recrystallized grain size ∼1 μm with profuse annealing twins was observed after annealing at 650 °C. Remarkable resistance against grain coarsening was observed at least up to 800 °C. The mechanisms for these features were closely related with the distinct whole-solute matrix in HEAs. The recrystallization texture was characterized by the retention of deformation texture components similar to those of TWIP and 316 stainless steels. But notable differences exist. The S ({1 2 3}〈6 3 4〉) component is stronger than brass ({1 1 0}〈1 1 2〉) and Goss ({1 1 0}〈0 0 1〉), and strengthened with increasing annealing temperatures. Strong α-fiber (〈1 1 0〉//ND) components other than the deformation components B S and G, and higher fraction of random components also develop. It could be attributed to profuse annealing twin formation due to the low stacking fault energy of the alloy.