Beyond traditional alloys: A critical review of lightweight high-entropy alloys from composition design to advanced manufacturing

• Elucidates multi-phase strengthening mechanisms that overcome the strength-ductility trade-off, including nano-twinning, heterogeneous structures, and coherent precipitation. • Integrates computational and experimental approaches covering thermodynamic modeling, machine learning-assisted design, and advanced manufacturing techniques such as additive manufacturing. • Highlights exceptional performance in extreme environments, including high-temperature strength, oxidation and corrosion resistance, wear resistance, and biocompatibility. • Proposes future research directions and application potential in aerospace, marine, and biomedical fields, providing a roadmap for next-generation lightweight structural materials. Lightweight high-Entropy Alloys (LWHEAs) overcome the performance limitations of traditional lightweight alloys through their exceptional specific strength, outstanding high-temperature stability, and superior corrosion resistance. Its decisive breakthrough lies in achieving outstanding performance characteristics at significantly reduced density, thereby addressing the critical weight challenge in structural applications of HEAs. This paper systematically reviews the development journey of LWHEAs—from fundamental design principles and simulation prediction to advanced manufacturing and multi-domain applications—and provides a multi-faceted and critical examination of their recent advancements. We elucidate the traditional trade-off between strength and ductility in LWHEAs through synergistic microstructure design—achieved by precisely controlling multi-major-element solid solutions, nanoscale precipitates, coherent interfaces, and deformation mechanisms. Further exploration of the interactions between composition, processing, and properties highlights how technologies such as additive manufacturing (AM) and spark plasma sintering (SPS) enhance material performance. This study also proposes specific development directions: integrating artificial intelligence with thermodynamic calculations, establishing corrosion fatigue testing standards, and advancing sustainable life cycle management. By synthesizing current cutting-edge findings, this review aims to establish a foundational framework for the continued development and application of LWHEAs in demanding fields such as aerospace, transportation, and biomedical engineering.