Synergistic strengthened mechanical properties and corrosion resistance of CoCrFeNiMnNb0.1 high-entropy alloy by cold rolling + annealing treatment

Herein, the microstructure of CoCrFeNiMnNb_0.1 high-entropy alloys (HEAs) is regulated by combination of cold rolling + annealing at different temperatures for investigating the evolution of mechanical properties and corrosion resistance, and to elucidate the underlying mechanisms of their synergistic strengthening. Cold rolling leads to high dislocation density and fragmentation of the Laves phases, resulting in a significant increase in hardness (~ 416 HV) due to dislocation strengthening. Accordingly, annealing at different temperatures influences the recrystallization and secondary phase precipitation, which causes the synergistic strengthening effect of multi-scale heterostructure evident. The alloys annealed @ 1000 ℃ exhibit excellent mechanical performance, with an ultimate tensile strength of 790.95 MPa and an elongation of 36.88%. This condition also produces favorable corrosion resistance, as evidenced by an increased pitting potential to 0.286 V_SCE and the formation of a denser passivation film that effectively suppresses pitting initiation. Therefore, the HEAs with synergistic strengthening effects play a significant role for exploring the high-strength, ductile, and corrosion-resistant functional materials especially suitable for marine and chemical environments.