Gradient cell–structured high-entropy alloy with exceptional strength and ductility

TLDR

Similar to conventional materials, most multicomponent high‑entropy alloys (HEAs) lose ductility as they gain strength. The study aims to introduce gradient nanoscaled dislocation cell structures in a stable single‑phase HEA to enhance strength without compromising ductility. Under strain, the structural gradient promotes progressive formation of numerous tiny stacking faults and twins that nucleate from abundant low‑angle dislocation cells. The resulting stacking‑fault–induced plasticity, refined microstructures, and accumulated dislocations collectively enhance strength, ductility, and work hardening, demonstrating a promising paradigm for tailoring nanoscale gradient dislocation cells in HEAs.

Abstract

Similar to conventional materials, most multicomponent high-entropy alloys (HEAs) lose ductility as they gain strength. In this study, we controllably introduced gradient nanoscaled dislocation cell structures in a stable single-phase HEA with face-centered cubic structure, thus resulting in enhanced strength without apparent loss of ductility. Upon application of strain, the sample-level structural gradient induces progressive formation of a high density of tiny stacking faults (SFs) and twins, nucleating from abundant low-angle dislocation cells. Furthermore, the SF-induced plasticity and the resultant refined structures, coupled with intensively accumulated dislocations, contribute to plasticity, increased strength, and work hardening. These findings offer a promising paradigm for tailoring properties with gradient dislocation cells at the nanoscale and advance our fundamental understanding of the intrinsic deformation behavior of HEAs.