Effect of annealing on the phase composition, microstructure and physical-mechanical properties' evolution of high-entropy CrMnFeCoNi2Cu Alloy

Abstract

The subject of this article is the investigation of thermal stability of the phase composition and physical-mechanical properties of the cold-rolled high-entropy multicomponent CrMnFeCoNi2Cu alloy. Non-equiatomic highentropy CrMnFeCoNi2Cu alloy is designed and fabricated by argon-arc smelting and room-temperature cold rolling up to 98% deformation. Thermal stability of phase composition, structure and physical-mechanical properties are studied after two-hour annealing at temperatures of 1073, 1173, 1273, 1373, 1473 K. As shown, the CrMnFeCoNi2Cu alloy in deformed state contains two f.c.c. phases (named as f.c.c.1 and f.c.c. 2). Annealing at 1273 K promotes the formation of f.c.c. 2 phase. After annealing above 1273 K, the f.c.c.1 phase enriched with Cu, Ni, and Mn is precipitated at the grain boundaries. A substantial grain-size increasing is observed after annealing at 1173 K. Level of microhardness remains stable up to temperature of 1273 K (0.84Tmelt). Effect of strengthening after cold plastic deformation is completely removed due to annealing at 1473 K for two hours. Recrystallization strain in high-entropy CrMnFeCoNi2Cu alloy lasts much slower than in most steels and alloys.