High cryogenic ductility of the high-entropy alloy CoCrFeNiAl0.1Ti0.05 at 77 K

Abstract

High-entropy alloys possess significant potential for material applications in demanding structural components subjected to extreme conditions. Through experimental investigations, we have validated that the CoCrFeNiAl0.1Ti0.05 high-entropy alloy, which was fabricated using a cold rolling and annealing process, exhibits an excellent balance of strength and ductility at 77 K. Specifically, it demonstrates a yield strength of 575 MPa, a tensile strength of 1145 MPa, and a ductility of 55%. This enhanced performance can be attributed to the altered deformation mechanism at low temperatures, leading to the multiplications of stacking faults and twins. Additionally, the introduction of small quantities of aluminum and titanium results in the formation of precipitated phases within the alloy matrix. The synergistic influence of these two factors contributes to the augmentation of cryogenic plasticity in the alloy.