Microstructure and mechanical property of Al,Ti co-adding L21-strengthened NiCrFe-based HEAs.

In this study, leveraging on the machine learning, a novel high-strength Ni 100-x-y Cr 25 Fe 25 Al x Ti y (x = 5, y = 5; x = 8, y = 7; x = 10, y = 10) high-entropy alloy (HEA) system was rationally designed, whose phase transformed from FCC + BCC to single BCC. The structural features, mechanical properties, and strengthening mechanism were systematically investigated. It has been discovered that the addition of Al and Ti can accelerate the formation of L21 phase. The Ni 35 Cr 25 Fe 25 Al 8 Ti 7 HEA shows outstanding comprehensive mechanical behavior, whose yield strength, compressive strength, fracture strain, and nano-hardness is 1913.69 MPa, 3896.62 MPa, 39.94%, and 11.07 GPa, respectively. These findings will give new insights into the controllable design of novel high-performance HEAs, enabling the achievement of target microstructures and superior combinations of properties. [Display omitted] • The phase selection was finished by using the machine learning. • The ordered L21 phase with multi-scale formed in the AlTi10 HEA. • The AlTi15 HEA displayed significantly comprehensive mechanical behaviors. • The solid-solution and precipitation strengthening contribution value was calculated. [ABSTRACT FROM AUTHOR]