Recent Advances on Lightweight High-Entropy Alloys: Process, Design, and Applications

With the rapid development of transportation and aerospace, energy consumption and pollutant emissions have increased significantly, putting great pressure on environmental protection. In order to promote the sustainable development of industry, the realization of metal lightweight on the premise of ensuring the comprehensive performance of metal parts has a great role in improving energy efficiency and reducing the emission of pollutants. Lightweight high-entropy alloys (LWHEAs), with excellent mechanical properties, have a broad application prospect in the field of metal lightweight, and have the potential to replace aluminum alloys as the next generation of lightweight metal materials. The research status and preparation methods of LWHEAs in recent years, including metallurgical smelting, powder metallurgy (PM), and additive manufacturing (AM) technologies, were reviewed. The microstructures and mechanical properties of LWHEAs were analyzed. Meanwhile, LWHEAs design strategies were discussed, including thermodynamic criteria, calculation of phase diagrams (CALPHAD), and machine learning (ML). The future research focus of LWHEAs should include the synthesis of new alloy systems and the development of new preparation technologies. The potential applications of LWHEAs in oxidation resistance and corrosion resistance were also discussed. LWHEAs will meet a huge market demand in the field of engineered materials, but many challenges remain, such as the trade-off between high strength and great ductility. We believe that this combination of knowledge may shape the future of LWHEAs, which requires significant breakthroughs in structural design and performance optimization for LWHEAs.