Designing Maximal Strength in Nanolamellar Eutectic High‐Entropy Alloys

Abstract Eutectic alloys have driven technological advancements for centuries, from early bronze tools that marked the dawn of metallurgy to high‐performance soldering materials. Building on this legacy, eutectic high‐entropy alloys (EHEAs) have recently emerged to push the boundaries of mechanical performance. However, the strength potential of EHEAs remains largely untapped, primarily because of limitations in cooling rates, posing a significant challenge to the development of ultra‐strong bulk EHEAs. This study employs large‐scale molecular dynamics simulations to uncover key insights into the design of EHEAs with exceptional mechanical performance. Simulations reveal that the maximum tensile strength occurs at a critical interphase boundary spacing, an order of magnitude larger than that observed in conventional alloys. Below this spacing, the governing mechanism shifts from the Hall–Petch strengthening to dislocation multiplication–mediated softening. Guided by the simulation insights, a tensile strength of 1.8 GPa is achieved for laser powder bed fusion–fabricated EHEAs. This strength approaches the theoretical limit and outperforms other state‐of‐the‐art as‐printed high‐entropy alloys. This work not only establishes a viable pathway for designing ultra‐strong EHEAs but also provides a promising avenue for addressing the long‐standing challenge of developing high‐performance as‐printed materials for aerospace and other demanding applications.