Fabrication, Mechanical, Corrosion and Electrocatalytic Properties Performance of Medium/High-Entropy Alloys and Their Applications

Medium- and high-entropy alloys (M/HEAs) are multi-principal-element metallic materials that overcome the performance limits of conventional single-principal alloys through four core effects: high entropy, severe lattice distortion, sluggish diffusion, and cocktail effect. They deliver exceptional mechanical properties from cryogenic to elevated temperature, superior corrosion resistance, and tunable electrocatalytic activity, making them promising for extreme-environment equipment, marine engineering, and clean energy conversion. This review covers: (1) key fabrication methods, including arc/induction melting, powder metallurgy, and nanoscale/thin-film processing; (2) multi-scale characterization of microstructure, mechanical behavior, corrosion response, and electrocatalysis; (3) mechanisms governing temperature-dependent mechanical performance; (4) synergistic passivation underlying corrosion resistance in aggressive media; (5) hydrogen/oxygen evolution reaction (HER/OER) electrocatalytic advantages, structure–activity relationships, and performance tuning strategies; (6) real-world applications in structural components, anti-corrosion systems, and energy devices; and (7) persistent challenges: imprecise synthesis control, unclear atomic-scale mechanisms, and trade-offs among multiple properties. Through cross-comparison of the reported data, three conclusions emerge: first, melt-based routes dominate bulk production, whereas powder metallurgy and severe-plastic-deformation routes are competitive for micro/nano-scale components and additive manufacturing remains limited by an immature process window; second, the strength–ductility and toughness trade-off across cryogenic-to-elevated temperatures is governed mainly by stacking-fault energy, transformation/twinning-induced plasticity, and precipitate stability; and third, the corrosion resistance and electrocatalytic activity of M/HEAs are tightly linked to passive-film chemistry and the configuration of active sites, rather than to configurational entropy alone. This review concluded with future priorities: artificial intelligence-driven composition design and low-cost, scalable manufacturing.