High-entropy Alloys For Applications Research Articles

Microstructure, mechanical and corrosion properties of FeCrNiCoMnSi0.1 high-entropy alloy coating via TIG arc melting technology and high-frequency ultrasonic impact with welding

With the increase in studies on high-entropy alloys and their impressive structural properties, the preparation processes and applications of high-entropy alloys have become a popular research topic in metallic materials. In this paper, the preparation of FeCrNiCoMnSi0.1 high-entropy alloy coatings was carried out by the follow-welding high-frequency power ultrasonic impact composite TIG arc melting process, the effects of different power ultrasonic impacts on the microstructure and properties of the coatings are investigated. The results showed that the average grain size is reduced by 74 % (from 278 μm to 72 μm), the average microhardness is increased by 41 % from 568 HV1 to 807 HV1, the abrasion resistance is improved by 68 % under the effect of ultrasonic impact. The ultrasonic impact treatment process can effectively refine the microstructure of the coatings and improve the strength of grain boundaries. The corrosion resistance of the coating in 3.5 wt% NaCl solution is enhanced by 65 %, the corrosion type was changed from intergranular corrosion to uniform corrosion. This is mainly caused by the ultrasonic impact treatment which suppresses the elemental segregation of Cr and Mn and improves the grain boundary strength.

Interstitial-oxygen induced and magnetically driven HCP-to-FCC transformation in CoCrFeNiOx high-entropy alloy: a first-principles study

ABSTRACT We report the influences of oxygen interstitials and magnetisms on phase stability and structural transformation of CoCrFeNi high-entropy alloy (HEA) from first-principles calculations. It is found the formation of oxygen interstitials is energetically favourable to occur in face-centred cubic (FCC) CoCrFeNiOx HEA as compared with that in hexagonal close-packed (HCP) one, and at those octahedral sites neighbouring with more Cr or less Ni. Meanwhile, it is determined the HEA prefers FCC over HCP phases when the oxygen concentration exceeds 4.2 and 5.1 at.% with and without considering its magnetisms, respectively. The HCP-to-FCC structural transformation in CoCrFeNiOx HEA could be magnetically driven, accompanied by the significant changes in the atomic magnetic moments in the HEA, particularly with an oxygen interstitial concentration larger than 2.7 at.%. Furthermore, the HCP-to-FCC transformation under hydrostatic pressure in CoCrFeNi and CoCrFeNiOx HEAs is investigated from generalised stacking fault energies, and it is revealed that the synergy effects of oxygen interstitials and magnetisms could facilitate the transformation in CoCrFeNiOx HEA. The coupled interstitials-induced and magnetically driven structural transformation paves a new avenue for the application of HEAs.

A green approach for decolorising azo dyes by using AlCrFeMn-based high-entropy alloys doped with nonmetallic elements (S, P and C)

The effects of nonmetallic elements Sulfur (S), Phosphorus (P) and Carbon (C) on the decolorisation of azo dye direct blue 6 (DB6) by using ball-milled (BM) Co-free AlCrFeMn (S0) high-entropy alloy (HEA) are presented for the first time in this work. We report the approach of adding S, P and C into S0 HEA in a single step by ball milling, and it is environment friendly method. Moreover, HEAs added with S, P and C do not cause secondary pollution of water during decolorisation recation. DB6 dye solution (200 mg/L) can be fully decolorised in 0.3, 1.9 and 3.3 min with 0.5 g/L of BM AlCrFeMnS (SS), AlCrFeMnP (SP), and AlCrFeMnC (SC), which are about 42, 6.6 and 3.8 times faster than that of S0, respectively. The efficiency of SS for DB6 is 126,000 times that of commercially available pure iron powders. The activation energy of SS is 36.3 kJ/mol, which is lower than that of S0 (54.6 kJ/mol). The extremely high decolorisation efficiency is closely related with the formation of a large number of galvanic cells in SS, SP and SC between the metal and nonmetal elements, which greatly increases the amount and efficiency of electron transfer. The decolorisation efficiency of DB6 solution is assessed by ultraviolet–visible absorption spectrophotometry. The decolorisation rate follows pseudo-first-order reaction kinetics with respect to dye concentration. The results of this study provide some enlightenment for researchers in the application of HEAs in wastewater treatment.

The understanding, rational design, and application of high-entropy alloys as excellent electrocatalysts: A review

The understanding, rational design, and application of high-entropy alloys as excellent electrocatalysts: A review

PtFeCoNiCu High-Entropy Alloy Catalyst for Aqueous-Phase Hydrogenation of Maleic Anhydride

High-entropy alloys (HEAs), as new heterogeneous catalytic materials, possess remarkable catalytic performance in numerous reactions. However, rational and controllable synthesis of these complex structures remains a challenge. In this work, bulk and carbon nanotube (CNT)-supported ultrasmall PtFeCoNiCu HEA nanoparticles with an average particle size of 1.58 nm are prepared by lithium naphthalenide-driven reduction under mild conditions. The supported PtFeCoNiCu/CNT catalyst exhibits high catalytic activity in the aqueous-phase hydrogenation of maleic anhydride to succinic acid with a selectivity of 98% at full conversion of maleic acid (the hydrolysis product of maleic anhydride), a low apparent activation energy (Ea = 49 kJ mol-1), and excellent stability. Moreover, a much higher mass-specific activity of Pt in the catalyst is displayed over PtFeCoNiCu/CNT (1515.4 mmolmaleicacid gPt-1 h-1) than that of 5 wt % Pt/CNT (388.0 mmolmaleicacid gPt-1 h-1). This work provides a strong support for HEAs as advanced heterogeneous catalysts and will be of great significance for promoting the research and application of HEAs in the field of selective hydrogenation.

Synthesis and characterization of nano-polycrystal diamonds on refractory high entropy alloys by chemical vapour deposition

Growing diamond has been a long-standing challenge. It is found the diamond grows on refractory metals (such as Zr, Hf, Ti) hardly to form a continuous film with a high nucleation density because of diffusion of carbon. In this study, we reported an approach to grow diamond on high entropy alloys (HEAs) of TiZrHfTaMo, TiZrHfNbMo, TiHfNbTaMo as substrates by chemical vapour deposition. Diamond films with a nucleation density as much as 108 ∼ 1010 site/cm2 grow on the mixed-carbides XC (X = Hf, Zr and Ta etc.) layer, which is 2 ∼ 3 orders of constituent metals. The orientation relationship is identified as diamond[011] // XC[001] with XC mixed-carbides by high resolution transmission electron microscope. The continuous diamond films can be obtained within 30 min. The high nucleation density and rapid growth on HEAs refer to solubility of carbon and relative nucleation energy barrier. Moreover, the corrosion of current specimens in 3.5 wt% NaCl solution have been improved (e.g., corrosion potential value is as much as −0.02 V/SCE) because of the continuous diamond film. Current result facilitates promising industrial applications of HEAs and diamonds by combining the advantages of them.

A molecular dynamics study of atomic diffusion effects on thermomechanical properties applying laser additive alloying process for the Cantor high entropy alloy

High entropy alloys (HEAs) can be manufactured in many conventional ways, but it becomes difficult to fabricate heterogeneous materials and structures. The Selective Laser Melting (SLM) method generally melts pure elemental powders or prefabricated alloy powders without an alloying process. In-situ alloying in SLM, which is also called Laser Additive Alloying (LAA), using pure elemental powders becomes a promising method for creating HEA with heterogeneous structures. However, the effect of the diffusion of elements in the molten pool on the formation of HEA remains unclear. In this paper, the well-discussed Cantor HEA was studied in an in-situ alloying situation, where pure elemental powders (Co, Cr, Mn, Ni, Fe) distributed on a powder bed were irradiated by laser and were subsequently allowed to cool back to room temperature. The diffusion of specific elements, with respect to their original clusters, was tracked via Mean Square Displacement (MSD) as well as the final composition of key locations. Our model was verified by showing a good agreement with the overall average diffusion rates of each element in the Cantor HEA qualitatively in other works from literature. Results initially showed that as the energy density increases, better diffusion was observed through a pixel overlay analysis focusing on the mixing of different elements. The best-case scenario of diffusion from the pixel overlay map indicated a strong presence of 3 to 4 elements after the laser scanning. Given the conditions in the MD simulation, there was no apparent segregation of elements during the alloying process. The solidified powder bed was sectioned into a 5 by 4 grid to analyze the composition of the entire powder bed. In addition, we also conducted a simulation by implementing a 0.03 nm/ps laser scanning in a meander 2-track scan to completely melt the powder bed. After cooling and equilibration, Polyhedral Template Analysis was applied to analyze the crystal structure of the solidified powder bed in the presence of increasing components. When alloying the Cantor alloy all elements experience a complex diffusion behavior, elements like Cr experience fairly rapid diffusion rates compared to other elements, despite this, Cr only diffuses for a short period and diffuses minimally during the process. The analysis of element-specific behavior, such as diffusion, can provide a framework for the LAA production of HEA. This MD study provides a detailed analysis about the effect of diffusion on the formation of HEA system if in-situ alloying is adopted, this study is further extended to analyze the effect of diffusion on the thermomechanical properties of HEAs. Moreover, Young's Modulus, Shear Modulus, and lattice thermal conductivity coefficient were simulated and compared with published experimental works. Lastly, the diffusion coefficients were calculated in 3 near-equimolar alloys and 3 alloys with various Fe atomic percentages to study the effects of entropy on the tracer diffusion rates. The findings in this study in terms of diffusion behavior can assist the design and manufacturing of other novel HEAs for applications in extreme environments.

Corrosion Behavior of High Entropy Alloys and Their Application in the Nuclear Industry—An Overview

With multiple principal components, high entropy alloys (HEAs) have aroused great interest due to their unique microstructures and outstanding properties. Recently, the corrosion behavior of HEAs has become a scientific hotspot in the area of material science and engineering, and HEAs can exhibit good protection against corrosive environments. A comprehensive understanding of the corrosion mechanism of HEAs is important for further design of HEAs with better performance. This paper reviews the corrosion properties and mechanisms of HEAs (mainly Cantor alloy and its variants) in various environments. More crucially, this paper is focused on the influences of composition and microstructure on the evolution of the corrosion process, especially passive film stability and localized corrosion resistance. The corrosion behavior of HEAs as structural materials in nuclear industry applications is emphasized. Finally, based on this review, the possible perspectives for scientific research and engineering applications of HEAs are proposed.

Optimization strategies of high-entropy alloys for electrocatalytic applications.

High-entropy alloys (HEAs) are expected to become one of the most promising functional materials in the field of electrocatalysis due to their site-occupancy disorder and lattice order. The chemical complexity and component tunability make it possible for them to obtain a nearly continuous distribution of adsorption energy curve, which means that the optimal adsorption strength and maximum activity can be obtained by a multi-alloying strategy. In the last decade, a great deal of research has been performed on the synthesis, element selection and catalytic applications of HEAs. In this review, we focus on the analysis and summary of the advantages, design ideas and optimization strategies of HEAs in electrocatalysis. Combined with experiments and theories, the advantages of high activity and high stability of HEAs are explored in depth. According to the classification of catalytic reactions, how to design high-performance HEA catalysts is proposed. More importantly, efficient strategies for optimizing HEA catalysts are provided, including element regulation, defect regulation and strain engineering. Finally, we point out the challenges that HEAs will face in the future, and put forward some personal proposals. This work provides a deep understanding and important reference for electrocatalytic applications of HEAs.

Comparison of CoCrFeNi coatings prepared via high-speed laser cladding and normal laser cladding on microstructure and properties

Two kinds of CoCrFeNi high entropy alloy coatings were prepared by normal laser cladding (N-) and high-speed laser cladding (HS-), respectively. The comparative analyses of crystallographic orientation distribution, microstructure, microhardness, wear resistance and corrosion resistance of both coatings were conducted. The results show that the phase structures of HS-CoCrFeNi and N–CoCrFeNi coatings are single FCC solid solutions. The dendrite size of HS-CoCrFeNi coating is only half of that of N–CoCrFeNi coating. The microhardness of HS-CoCrFeNi coating (380 HV0.2) is about 2.3 times that of N–CoCrFeNi coating (165 HV0.2), due to the combined effect of grain refinement, dispersion strengthening and dislocation strengthening. The wear resistance and corrosion resistance of HS-CoCrFeNi coating are better than N–CoCrFeNi coating. With the increase of friction speed, the same wear mechanism of the two coatings is obtained, changing from abrasive wear to adhesive wear and fatigue wear. High-speed laser cladding is a promising technology to promote the development and application of high entropy alloys in the industry.

High-Entropy Materials in SOFC Technology: Theoretical Foundations for Their Creation, Features of Synthesis, and Recent Achievements.

In this review, recent achievements in the application of high-entropy alloys (HEAs) and high-entropy oxides (HEOs) in the technology of solid oxide fuel cells (SOFC) are discussed for the first time. The mechanisms of the stabilization of a high-entropy state in such materials, as well as the effect of structural and charge factors on the stability of the resulting homogeneous solid solution are performed. An introduction to the synthesis methods for HEAs and HEOs is given. The review highlights such advantages of high-entropy materials as high strength and the sluggish diffusion of components, which are promising for the use at the elevated temperatures, which are characteristic of SOFCs. Application of the medium- and high-entropy materials in the hydrocarbon-fueled SOFCs as protective layers for interconnectors and as anode components, caused by their high stability, are covered. High-entropy solid electrolytes are discussed in comparison with traditional electrolyte materials in terms of conductivity. High-entropy oxides are considered as prospective cathodes for SOFCs due to their superior electrochemical activity and long-term stability compared with the conventional perovskites. The present review also determines the prioritizing directions in the future development of high-entropy materials as electrolytes and electrodes for SOFCs operating in the intermediate and low temperature ranges.

Single-step electrochemical synthesis of nano-crystalline CoCrFeNi high-entropy alloy powder

The difficulty of producing high-entropy alloy (HEA) powders is one of the key issues that limits the application of HEAs in a range of fields, including energy devices, additive manufacturing and spraying techniques. In the present work, nano-size equiatomic CoCrFeNi HEA powder has been prepared from micro-size mixed metal-oxide precursors by electro-deoxidation in molten CaCl2-NaCl at 923 K. The HEA powder obtained had a single-phase face-centered cubic structure with a lattice constant of 3.571 Å, and was of a powdery morphology with spherical particles in the size range of 40–200 nm. The composition achieved was close to the nominal one and no contamination was detected. Altogether, this study has demonstrated that, with suitably adjusted process parameters, electro-deoxidation is an effective method of producing nano-size HEA powders.

Review of High Entropy Alloys Electrocatalysts for Hydrogen Evolution, Oxygen Evolution, and Oxygen Reduction Reaction.

Recently, high-entropy alloys (HEAs) have been extensively investigated due to their unique structural design, superior stability, excellent functional feature and superior mechanical performance. However, most of the reported HEAs focus on studying the compositional design and microstructure and mechanical properties of materials. There are relatively few studies on electrochemical performance and theoretical studies of HEAs. In addition, the potential applications of HEAs as energy storage materials for electrocatalysts have attracted widely attention in the development and application aspects of electrocatalysis. It can be attributed to their high conductivity, excellent structural stability and superior electrocatalytic activities with small overpotential and abundant active sites, which is comparable to the commercial noble metal catalysts. In this review, firstly, we briefly discuss the concept and structure characteristics of high entropy alloys. Then, the research progress of high-entropy alloys as electrocatalysis are also summarized, including hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and oxygen reduction reaction (ORR), respectively. Finally, the future development trend of HEAs is also prospected for energy conversion fields.

FeCoNiMnCuTi high entropy amorphous alloys and M50Ti50 (M = Fe, Cu, FeCoNiMnCu) amorphous alloys: Novel and efficient catalysts for heterogeneous photo-Fenton decomposition of Rhodamine B

Traditional Fe based amorphous alloys (Fe-Si-B system) with good Fenton-like performance have attracted great attention in dye wastewater decomposition. However, their relative low catalytic stability, narrow pH working range and expensive constituent elements impede the corresponding application. In addition, discovering new application of high entropy alloys in catalytic degradation besides decolorization of azo dyes has already been a scientific research hotspot. Consequently, in this work, M50Ti50 (M = Fe, Ni, Cu, FeCoNiMnCu) amorphous alloys, FeCoNiMn high entropy alloys and FeCoNiMnCuTi high entropy amorphous alloys were prepared by one-step ball milling method and then used as Fenton-like catalysts. The average particle sizes of the prepared Fe50Ti50, Ni50Ti50, Cu50Ti50, (FeCoNiMnCu)50Ti50, FeCoNiMn and FeCoNiMnCuTi were measured to be 22.3, 27.8, 26.5, 17.1, 15.4 and 19.5 μm, respectively. Among them, Fe50Ti50, Cu50Ti50, (FeCoNiMnCu)50Ti50 and FeCoNiMnCuTi exhibited superior photo-Fenton performances: 4 min UV decomposition rates of RhB solution are up to 82.77%, 85.96%, 75.23% and 88.19%, respectively, which would be the promising Fenton-like catalysts for industrial dye wastewater treatment. In particular, this is the first report on dye degradation behavior of equiatomic high entropy amorphous alloys and Cu based amorphous alloys were firstly developed to be a photo-Fenton catalyst.

Research of high entropy alloys as electrocatalyst for oxygen evolution reaction

High entropy alloys (HEAs) have been the focus of research as a new class of multi-metal alloys due to their outstanding corrosion resistance, radiation stability, and superior mechanical properties. Unfortunately, there are still limitations in the current research on the characteristics of HEA, which can’t satisfy the wide application of HEAs. Therefore, it is critical to focus the research on the functional aspects of HEAs to achieve their maximum potential. It is exciting that the complex surface chemistry and flexibility of HEAs in shaping unique functions, have been proven to be excellent materials for catalysts in recent years. The superior functionality of HEAs has led to a rapidly growing demand for them. In particular, HEAs as electrocatalysts for oxygen evolution reactions (OER) have become a hot spot for research. However, the applicability of the HEA as catalysts is affected by various factors such as elemental composition, preparation method, surface morphology. The limited research work and unclear catalytic mechanism of HEA electrocatalysts result in the widespread high overpotential, which hinders the application of high entropy electrocatalysts. This paper summarizes the morphological engineering, derived compositional engineering, synthetic methods, electrical properties of the HEA and their derivatives, and applicability as catalysts. Moreover, the paper highlights the challenges and perspectives for the development of high entropy electrocatalysts in order to provide valuable guidance for future research on HEA and its derivatives in the field of OER. • The main preparation method and control strategy of high-entropy catalysts were summarized. • The advantages and disadvantages of high-entropy electrocatalysts and other types of electrocatalysts were introduced. • The opportunities and challenges of high-entropy materials as electrocatalysts in the future were discussed.

Atomistic simulations to study shock and ultrashort pulse response of high entropy alloy

This article aimed to study the shock compression and ultrashort pulse shock compression behavior of multi-elemental alloy, high entropy alloy (HEA), and single-crystal Ni. Non-equilibrium molecular dynamics (NEMD) based simulations were utilized in this article with the help of EAM potential to capture the deformation under dynamic and complex loading scenarios in HEA (Co-Cr-Cu-Fe-Ni) and single-crystal Ni. Simulations were performed with continuous shock compression and ultra-short shock pulse traversing the atomic configuration at velocity 0.75 km/s. Simulation helps capture the distribution of pressure and velocities in the simulation box as a function of the time from the onset of the shock front. Simulation helps capture the distribution of pressure and velocities in the simulation box as a function of the time from the beginning of the shock front. It was concluded from the MD simulations that the insertion of nano-voids in the path of the shock front helps in dispersing the energy and reducing the speed of the shock front. Nano-voids significantly affect the shock deformation of crystals and help in inducing plastic deformation in the HEA and Ni, even at shock velocities below Hugoniot elastic limit (HEL). Nucleation of dislocation from the nano-voids is more significant in HEA crystal as compared to Ni. The onset of plastic deformation in HEA and higher dislocation densities helps in dispersing the energy of the shock front, and the performance of HEA improved at higher shock velocities. The results in this article will help develop high entropy alloys for applications containing complex loading scenarios such as high strain rate loading experienced in space structures and armor vehicles.

Application progress of high-entropy alloys in brazing field: A short review

Multi-component high-entropy alloys (HEAs) have intrigued intensive attentions in the metallic materials fields due to their unprecedented properties including excellent radiation resistance, exceptional strength-ductility synergy at cryogenic temperature and good high-temperature stability. As such, HEAs are promising candidates for many engineering applications in extreme environment. To promote the fabrication and application of HEAs, exploiting HEAs-brazing technique is indispensable due to its cost-effectiveness, simplicity and excellent adaptability to sample configuration. Besides, owing to high-entropy and sluggish diffusion effects, HEAs also can be used as brazing filler metals in the brazing technology. The short review first discusses the brazing of HEAs with different fillers, and the interfacial microstructures and joining properties are summarized. Subsequently, the brazing of traditional ceramics to themselves or to metals with novel HEA filler metals is introduced. Besides, the summary and expectation of the coming research topics are also listed in the conclusions.

On the phase constituents of three CoCrFeNiX (X = B, Al, Ga) high-entropy alloys after prolonged annealing

Equilibrium or near-equilibrium phase data are crucial to the development and application of high entropy alloys (HEAs). However, the vast majority of published HEA phase data are based on as-cast or shortly annealed conditions. Here, the phase constituents and microstructures in three equimolar CoCrFeNiX alloys (X = B, Al, Ga) after prolonged annealing at 500–1100 °C have been investigated. The CoCrFeNiB alloy was comprised of a dominating FCC phase and various boride phases [(Cr, Fe)2B, (Fe, Co, Ni)3B, Cr2B-tI12] at all annealing temperatures. Annealing at 700 °C led to the additional formation of CrB. The CoCrFeNiAl alloy was comprised of B2, BCC, and FCC phases at 1100 and 500 °C. The BCC phase transformed to the sigma phase at 700 and 900 °C. The CoCrFeNiGa alloy was comprised of BCC and FCC phases at all annealing temperatures, with additional sigma phase formation at 700 °C and 500 °C. The experimental results were compared with CALPHAD predictions. Depending on the alloy system, the accuracy of CALPHAD calculations varied significantly. The accuracies are well-related to the fraction of assessed systems of each alloy. These data here are not only useful as individual alloys. Together with previous parts of this systematic study, which investigated X elements from groups IVB, VB, and VIB (Y, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W), the holistic dataset offers the basis for new analysis and interpretations when looked at in its totality. We expect that this dataset will be valuable for future studies on the phase formation and other aspects of HEAs.

Application of high-entropy alloys

From accumulated information on structure, properties, stability, and methods of manufacturing the high-entropy alloys (HEA) created early in the 21 century it follows that they possess a whole complex of useful properties that suggests their perspective application in different branches of industry. The authors have made a short review of scientific articles on analysis of possibilities of HEA application in specific science-consuming branches of the last 5 years. In biomedicine the protective coatings made of (TiZrNbHfTa)N and (TiZrNbHfTa)O HEAs possess biocompatibility, high level of mechanical properties, high wear- and corrosion resistance in physiological media, and excellent adhesion. Products made of (MoTa)χNbTiZr passed clinical tests successfully when being implanted to living muscular tissue. The developed HEAs based on rare-earth elements and metals of Fe group such as YbTbDyAlMe (Me = Fe, Co, Ni) possess magnetocaloric effect, have Curie temperature close to room one and may be used in modern refrigerator mechanisms. Changing in stoichiometric composition of CoCrFeNiTi HEAs, alloying them and performing thermal treatment, the researchers succeed in obtaining soft magnetic materials. Fields of HEA application are presented as following: catalysts of ammonia oxidation - (PtPdRhRuCe), ammonia decomposition - (RuRhCoNiIr), oxidation of aromatic alcohols - (Co0,2Ni0,2Cu0,2Mg0,2Zn0,2 ), electric catalysts of hydrogen extraction - (Ni20Fe20Mo10Cr15Co35 ), redox reactions (AlCuNiPtMn and AlNiCuPtPdAu), and oxidation of methanol/ethanol. HEAs can be used as electrodes - anodes and cathodes for Li-ion and Na-ion accumulators. Synthesized nanoporous HEA AlCoCrFeNi has high bulk density up to 700 F/cm3 and cyclic stability (>3000 cycles) and is used in supercapacitors. High-entropy oxides such as (MgNiCoCuZn)0.95Li0.05O with high dielectric properties in a wide frequency range may be used in electronic converters. Examples of HEA application are given: as coatings of ship parts being operated in sea water, various welded joints, parts of nuclear reactors. Perspectives of widening the fields of HEA application are indicated.

High‐entropy alloys and compounds for electrocatalytic energy conversion applications

AbstractHigh‐entropy materials, composed of five or more elements in near‐equiatomic percentage, have been attracting tremendous interests due to their advantageous properties in a variety of applications. Recently, electrocatalysis on high‐entropy alloys (HEAs) and high‐entropy compounds (HECs) has emerged as a new and promising material owing to the tailored composition and the disordered configuration of HEAs and HECs. Though extensive efforts have been devoted to investigating the catalytic nature of HEAs and HECs, the details related to the active sites and intrinsic activity of such catalysts still remain uncertain due to the complexity of the multicomponent systems. In this review, the recent progress of HEAs and HECs is systematically reviewed in terms of their synthetic strategies and electrocatalytic applications. Importantly, the computationally assisted methods (e.g., density functional theory [DFT]) are also presented to discover and design the optimum HEA‐ and HEC‐based catalysts. Subsequently, the applications of HEAs and HECs in electrocatalytic energy conversion reactions will be discussed, including hydrogen evolution reaction, oxygen evolution reaction, oxygen reduction reaction, carbon dioxide reduction reaction, nitrogen reduction reaction, methanol oxidation reaction, and ethanol oxidation reaction (EOR). Moreover, the prospects and future opportunities for this research field are cautiously discussed. A series of upcoming challenges and questions are thoroughly proposed from the experimental and theoretical aspects as well as other future applications in electrocatalysis.