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

Abstract

In this study, leveraging on the machine learning, a novel high-strength Ni100-x-yCr25Fe25AlxTiy (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 Ni35Cr25Fe25Al8Ti7 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.