Atomic-level understanding of enhanced mechanical properties in FeNiCrCoCu high-entropy alloy

Abstract

The FeNiCrCoCu HEA has attracted numerous attentions due to its exceptional strength at low temperatures. However, the emergence of its excellent mechanical properties still remains a mysterious issue till now. Focused on the strengthening mechanism of FeNiCrCoCu HEA, we explore the role of FCC phase and atomic clusters through 4 different simulation methods and varied cooling rates by employing molecular dynamics simulations. Results show that the direct preparation leads to the superior tensile strength and elongation among the 4 achieved samples, which is related to the increasing FCC phase fraction. Moreover, the increased FCC phase is further realized through the decreasing cooling rate, which is due to the extended relaxation time for atomic rearrangement. Furthermore, the contribution of FCC phase to enhanced mechanical properties is primarily attributed to the dominant 1421 bond pair and < 0,4,4,6 > cluster at the atomic-level. This research reveals the correlation between mechanical properties and atomic-level microstructure, which benefits the design of HEAs with desirable mechanical properties by modulating the microstructure.