Abstract: In this study, a high entropy alloy (HEA) with remarkable mechanical performance and corrosion resistance was fabricated through L1₂ precipitation strengthening. The tensile test at room temperature revealed that the CoCrFeNi₂Al_0.2Ti_0.2 HEA, with the highest L1₂ precipitate content, exhibited the most outstanding combination of mechanical properties characterized by a yield strength of 1656 62 MPa, a tensile strength of 187694 MPa, and excellent ductility of 21 % 1.0 %. The remarkable strength was primarily attributed to the synergistic strengthening effects of precipitation strengthening and grain boundary strengthening, whereas the excellent ductility correlates with the combined mechanisms of dislocation slip, deformation-induced stacking faults, and the Lomer-Cottrell locks. Electrochemical tests demonstrated a significant improvement in corrosion resistance with the introduction of L1₂ precipitates. X-ray photoelectron spectroscopy analysis further revealed that the increased corrosion resistance resulted from a higher concentration of corrosion-resistant components in the passivation film, facilitated by the presence of L1₂ precipitates. First-principles calculations revealed that the enhanced corrosion resistance is due to the higher work function and lower adsorption energy of the L12 precipitates compared to the matrix phase contributes to the superior performance. This research provides valuable insights into the fabrication of high-performance alloys and offers theoretical guidance for developing next-generation materials with optimized properties.

Key words: High entropy alloy, Ultrahigh strength, Corrosion, First-principles calculations, Passive film