Effect of rolling and annealing temperature on the mechanical properties of CrMnFeCoNi high-entropy alloy

Abstract

Equiatomic CrMnFeCoNi high-entropy alloy was cold- and hot-rolled (room temperature and 700 °C) to a thickness reduction of 90%. Subsequently, the rolled samples were annealed for 1 h at temperatures between 450 °C and 800 °C. The microstructure and texture of as-rolled and annealed samples were studied by scanning electron microscopy coupled with electron backscatter diffraction and energy-dispersive X-ray spectroscopy. The evolution of microstructure and texture has been found to be governed by dislocation slip, recrystallization and annealing twin formation. Moreover, during processing at certain temperatures concurrent precipitation is observed. The mechanical properties of all samples were derived from tensile stress-strain curves determined at room temperature. Based on microstructural analyses the strength of the thermo-mechanically processed samples can be quantitatively explained by a combination of different strengthening mechanisms, such as dislocation, grain boundary and precipitation hardening. • Mechanical properties of CrMnFeCoNi HEA can be extensively tailored by thermo-mechanical processing. • Recovery and partial recrystallization are the most important factors for optimization of strength and ductility. • Precipitation is counterproductive, but plays a subordinate role.