Research progress on high-entropy alloy powders

ZHANG Weidong; ZHANG Xichen; CAO Yuankui; PENG Fei; ZHU Baohui; LI Xiaoping; WU Zhenggang

doi:10.13732/j.issn.1008-5548.2025.03.001

Abstract：Significance High-entropy alloys(HEAs),as a new complex multi-principal element alloys,exhibit unique design and excep-tional physical and chemical properties,showing great potential in structural materials,functional materials,and biomedical applications.This study analyzes the advantages,disadvantages,and industrial prospects of existing preparation methods for HEA powders,offering insights for the development of new preparation methods and large-scale production tailored to different application scenarios. Progress HEA powder preparation techniques include mechanical alloying(MA),atomization,radio frequency plasma spheroidization(RFPS),plasma arc discharge(PAD),and chemical reduction(CR).MA can produce single-phase face-centered cubic(FCC)or body-centered cubic(BCC)HEA powders,as well as powders with complex phase structures.Gas atomization produces powders with high purity,low oxygen content,uniform composition,excellent sphericity,and minimal impurities,making it suitable for thermal spraying,refractory high-entropy alloy(RHEA)production,and injection molding,with broad application prospects.Water atomization is cost-effective,efficient,and suitable for large-scale production,though it produces powders with inferior sphericity and higher impurity levels compared to gas atomization.Plasma rotating electrode process(PREP)excels in producing spherical metal powders with ultra-low gap element content,featuring high sphericity,minimal satellite particles,and negligible hollow powders,though it yields powders with larger particle sizes and low fine pow-der production rates.RFPS,characterized by high temperature and enthalpy(≥8000℃),large plasma torches,and control-lable plasma atmospheres,has significant advantages in preparing spherical RHEA powders with high sphericity,minimal inter-nal defects,controllable particle size,good flowability,and uniform composition.However,this method requires pre-alloyed powders prepared via MA or spray drying,resulting in longer production cycles and lower efficiency.PAD and CR are primarily used to produce high-entropy alloy nanoparticles(HEA-NPs),yielding powders with fine,uniform particle sizes,high purity,large specific surface areas,and excellent catalytic stability.HEA powders are mainly applied in structural components through powder metallurgy,additive manufacturing,coatings,and films,as well as in catalysis and hydrogen storage.In structural applications,HEA powders serve as raw materials,while in catalysis and hydrogen storage,they are used directly as the final materials.HEA powders are commonly used in powder metallurgy to prepare structural components.These powders,typically elemental mixed powders or pre-alloyed powders,are processed through ball milling/mixing,pressing,sintering,and subse-quent treatments to produce bulk HEA materials.The high uniformity of powder materials in powder metallurgy effectively miti-gates issues such as compositional segregation,dendrite formation,and multiphase precipitation,which are common in tradi-tional casting,resulting in uniform HEA solid solution materials with excellent comprehensive properties.Additive manufactur-ing of HEAs has advanced rapidly,although early research was constrained by challenges in spherical powder production.As a result,the raw materials for additive manufacturing of HEAs primarily consisted of mixed elemental powders.Since 2015,gas-atomized HEA powders have been successfully used in additive manufacturing,enabling the production of multi-principal ele-ment HEA systems through laser additive technologies.HEA coatings and films exhibit properties similar to bulk HEAs,finding applications in high-temperature,anti-corrosion,and wear-resistant environments.These powders are used to prepare hard pro-tective coatings for tools and molds.They can also be used to produce thin-film materials with excellent toughness,high fatigue resistance,and electrical resistivity,suitable for flexible electronic devices and micro-electromechanical systems.HEA-NPs offer unique advantages in electrocatalysis,including abundant active sites,high flexibility,strong cascade reactions,and opti-mized adsorption site electron structures.Additionally,HEA powders are promising hydrogen storage materials due to the sig-nificant lattice distortion of BCC HEAs and the varying atomic radii,which create large interstitial spaces and enhance matrix-hydrogen bonding.The multi-principal-element characteristic further enhances the binding energy between the matrix and hydrogen.The selection of HEA powder preparation techniques should prioritize the required powder properties and process characteristics for specific applications,while considering economic viability,environmental impact,and scalability. Conclusions and Prospects Over the past decade,significant progress has been made in the preparation and application of HEA powders,with preliminary explorations into market-oriented production and application feasibility.However,many chal-lenges remain in the field of HEA powders,and future research should focus on the following key areas.The development of HEA powders still relies on traditional metal powder preparation theories.Given the complex compositions and diverse elements of HEAs,new theories tailored to different HEA systems should be developed.Existing preparation techniques primarily stem from conventional metal powder processes,which face significant challenges in producing RHEA powders with uniform composi-tions and microstructures.Future research should aim to combine new theories with innovative methods and technologies for HEA powder preparation.Systematic studies on the large-scale production of HEA powders are limited.Future efforts should enhance research in this area,focusing on improving existing scalable preparation techniques,developing new processes,and addressing cost control and environmental concerns to accelerate market-oriented production.While HEA powder applications in structural materials have been widely studied,research into their use in functional materials,such as energy storage,magne-tism,and catalysis,remains in its initial stage.Given their immense potential in these fields,functional HEA powders are expected to become a research focus in both fundamental theory and engineering applications,especially in areas such as compo-sition design,ultra-fine powder preparation,performance optimization,and mechanisms to drive foundational and engineering applications of functional HEA powders.