Application of High-Entropy Alloys

From the accumulated data on the structure, properties, stability, methods for obtaining high-entropy alloys (HEAs), created at the beginning of the 21st century, a whole range of useful properties were discovered, which allows for promising usages in various industries. A brief review of the literature from the last five years on the analysis of using HEAs in specific knowledge-intensive industries is carried out. In biomedicine, protective coatings made of HEAs (TiZrNbHfTa)N and (TiZrNbHfTa)O possess biocompatibility, a high level of mechanical properties, high wear and corrosion resistance in physiological environments, and excellent adhesion. (MoTa)xNbTiZr products have successfully passed clinical trials when implanted in living muscle tissue. The developed HEAs based on rare earth elements and metals of the Fe group of the YbTbDyAlMe type (Me = Fe, Co, Ni) have a magnetocaloric effect, have the Curie point close to room temperature, and can be used in modern refrigeration devices. By changing the stoichiometric composition of the CoCrFeNiTi HES, alloying them and conducting heat treatment, it is possible to obtain soft magnetic materials. The application fields of HEAs as catalysts for ammonia oxidation (PtPdRhRuCe), decomposition of ammonia (RuRhCoNiIr), oxidation of aromatic alcohols (Co0.2Ni0.2Cu0.2Mg0.2Zn0.2), electrocatalysts for the evolution of hydrogen (Ni20Fe20Mo10Cr15CutPi, redox reactions (AlCuNiPtMn and AlNiCuPtPdAu), and methanol/ethanol oxidation are considered. HEAs can be used as electrodes-anodes and cathodes for Li-ion and Na-ion batteries. Synthesized nanoporous AlCoCrFeNi HES have a high bulk density (up to 700 F/cm3) and cyclic stability (>3000 cycles) and are used in supercapacitors. High-entropy oxides of the (MgNiCoCuZn)0.95Li0.05O type with high dielectric properties in a wide frequency range can be used in electronic converters. Examples of HEAs application as coatings for parts of watercrafts operating in sea water, dissimilar welded joints—parts of nuclear reactors—are given. Prospects for expanding the areas of HEAs application are noted.