Multi-scale microstructure strengthening strategy in CoCrFeNiNb0.1Mo0.3 high entropy alloy overcoming strength-ductility trade-off

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 882; p. 145446
• Main Authors: Fan, Rui, Guo, Erjun, Wang, Liping, Wang, Lei, Zhao, Sicong, Li, Xuemei, Zhang, Xin, Cui, Bo
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 24.08.2023
• Subjects: Annealing; High entropy alloy; Mechanical properties; Precipitate; Short-range order; Mechanical properties; Short-range order; Annealing; Precipitate; High entropy alloy
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2023.145446

Improving the strength of CoCrFeNi high entropy alloy with a face-centered cubic structure has been a subject of significant research in recent years. However, most strengthening mechanisms are limited by the strength-ductility trade-off. In this study, we proposed an entirely new strategy of multi-scale microstructure strengthening for high entropy alloys that significantly enhances the yield strength and ultimate tensile strength to 751 MPa and 1100 MPa, respectively, while maintaining high elongation of 15.1%. Through annealing at different temperatures, we tailored the microstructure of CoCrFeNiNb0.1Mo0.3 alloy, in which a multi-scale microstructure was achieved through inducing the micro-scale Laves phase, nano-scale precipitate and atomic-scale short-range order structure. Through Orowan bypass mechanism and shearing mechanism, the synergistic interaction effect of multi-scale reinforcements can realize a breakthrough in mechanical properties to further overcome strength-ductility trade off, and thus demonstrate a promising approach to improve engineering performance of high entropy alloys. [Display omitted] •Through adjusting the annealing temperature, the tailoring of microstructure with large cross-scales is achieved.•A breakthrough in the mechanical properties of the alloy is achieved through the construction of multi-scale microstructure.•Multi-scale microstructure strengthening strategy overcome strength-ductility trade-off in HEAs.