Effect of annealing treatments on microstructure and mechanical properties of high-entropy alloy Cr10 Mn10Fe60Co10Ni10

Abstract

A face-centered cubic (FCC) non-equiatomic high-entropy alloy (HEA), Cr10Mn10Fe60Co10Ni10, is processed via cold-rolling and subsequent annealing at 800−1200 °C with different cooling methods. All the annealing treatments lead to fully recrystallized microstructures with various grain sizes and precipitate types. The mechanical properties under uniaxial tension are obtained along with microstructure characterizations of postmortem samples. The sample annealed at 800 °C followed by furnace cooling yields a reasonable combination of high strength and good ductility. The yield strength and ultimate tensile strength are 43% and 19% higher than those of the sample annealed at 800 °C followed by water quenching, with only a uniform elongation ∼6% reduction. The yield strength variations of all the annealed samples are explained with a structure-based strength model. After fracture, all the samples show strong 〈111〉 texture along the tensile direction. Besides dislocation slip, deformation twinning and multiple phase transitions contribute to high strength and effective work hardening as additional deformation mechanisms. The newly formed hexagonal close-packed and body-centered cubic phases follow the Shoji–Nishiyama and Kurdjumov–Sachs orientation relations with the FCC matrix, respectively. Given the “treatment method−microstructure−mechanical property” relationship in this study, combining the advantages of the steel and HEAs, this kind of Fe-rich HEA bears great potentials to serve under practical conditions.