Mechanical Behaviors of Cold-Rolled and Subsequently Annealed Fe35Ni35Cr20Mn10 High-Entropy Alloy

The effects of cold rolling and subsequent annealing on the microstructure and mechanical behaviors of Fe35Ni35Cr20Mn10 (in at.%, unless otherwise stated) high-entropy alloys (HEAs) were investigated by microstructure observation and mechanical property testing. The cold rolling results in a significant rise in the strength of the prepared HEA but a great reduction in the fracture elongation. The dominant fine subgrain structure and much higher density of dislocations in the as-rolled sample are responsible for this phenomenon. The combined effects of the significantly decreased dislocation density, obviously coarsened recrystallization grains, and considerable reduction in the amount and significant coarsening in the size of the annealing twins with the annealing temperature decreased the yield strength, but the elongation improved significantly. The prepared Fe35Ni35Cr20Mn10 HEA annealed at 800 °C for 1 h after cold rolling has a good combination of strength and elongation, with a high yield strength of ~ 336 MPa, a high ultimate tensile strength of ~ 525 MPa, and an excellent elongation to fracture of ~ 44%.