A Heterogeneous Cantor Alloy with Ultrahigh Yield Strength under Extreme Loading

Cantor alloys are favored for their excellent fracture toughness at low temperatures. However, a face-centered cubic structure limits yield strength, rendering it unsuitable for the demanding requirements of extreme environments. Here, we achieved a dynamic yield strength exceeding ∼1.3 GPa for Cantor alloys under liquid nitrogen temperature, both at strain rates of 1800 and 2100 s^-1, by constructing multilevel heterogeneous structures. This ultrahigh strength was demonstrated to originate from a combination of dislocation strengthening, Hall-Petch strengthening, twin strengthening, and strengthening from nanoscale planar defects. Unexpectedly, this heterogeneous-structured alloy also showed prominent strain hardening, indicating excellent energy absorption capacity under extreme loading. Molecular dynamics simulations further revealed that nanotwins and 9R phases played a vital role in hindering dislocation slips and promoting the formation of immobile stair-rod dislocations, thus contributing to effective strain hardening. These findings provide important implications for the development of advanced materials for extreme environments.