High-entropy alloys(HEAs),which were introduced as a pioneering concept in 2004,have captured the keen interest of nu-merous researchers.Entropy,in this context,can be perceived as representing disorder and randomness...High-entropy alloys(HEAs),which were introduced as a pioneering concept in 2004,have captured the keen interest of nu-merous researchers.Entropy,in this context,can be perceived as representing disorder and randomness.By contrast,elemental composi-tions within alloy systems occupy specific structural sites in space,a concept referred to as structure.In accordance with Shannon entropy,structure is analogous to information.Generally,the arrangement of atoms within a material,termed its structure,plays a pivotal role in dictating its properties.In addition to expanding the array of options for alloy composites,HEAs afford ample opportunities for diverse structural designs.The profound influence of distinct structural features on the exceptional behaviors of alloys is underscored by numer-ous examples.These features include remarkably high fracture strength with excellent ductility,antiballistic capability,exceptional radi-ation resistance,and corrosion resistance.In this paper,we delve into various unique material structures and properties while elucidating the intricate relationship between structure and performance.展开更多
This review focuses on thermodynamic and physical parameters,synthesis methods,and reported phases of Magnesium(Mg)containing high-entropy alloys(HEAs).Statistical data of publications concerning Mg-containing HEAs we...This review focuses on thermodynamic and physical parameters,synthesis methods,and reported phases of Magnesium(Mg)containing high-entropy alloys(HEAs).Statistical data of publications concerning Mg-containing HEAs were collected and analyzed.Data on the chemical elements included in Mg-containing HEAs,their theoretical end experimental densities,thermodynamic parameters,physical parameters,fabricated techniques and reported phases were also collected and discussed.On the basis of this information,a new classification for HEAs was proposed.It is also shown that the existing thermodynamic parameters cannot accurately predict the formation of a single phase solid solution for Mg-containing HEAs.The physical parameters of Mg-containing HEAs are within a wide range,and most of the synthesized Mg-containing HEAs have a complex multiphase structure.展开更多
A series of high-entropy alloys(HEAs) containing nanoprecipitates of varying sizes is successfully prepared by a non-consuming vacuum arc melting method.In order to study the irradiation evolution of helium bubbles in...A series of high-entropy alloys(HEAs) containing nanoprecipitates of varying sizes is successfully prepared by a non-consuming vacuum arc melting method.In order to study the irradiation evolution of helium bubbles in the FeCoNiCrbased HE As with γ' precipitates,these samples are irradiated by 100-keV helium ions with a fluence of 5 × 10~(20) ions/m~2 at 293 K and 673 K,respectively.And the samples irradiated at room temperature are annealed at different temperatures to examine the diffusion behavior of helium bubbles.Transmission electron microscope(TEM) is employed to characterize the structural morphology of precipitated nanoparticles and the evolution of helium bubbles.Experimental results reveal that nanosized,spherical,dispersed,coherent,and ordered L1_2-type Ni_3Ti γ' precipitations are introduced into FeCoNiCr(Ni_3Ti)_(0.1) HEAs by means of ageing treatments at temperatures between 1073 K and 1123 K.Under the ageing treatment conditions adopted in this work,γ' nanoparticles are precipitated in FeCoNiCr(Ni_3Ti)_(0.1) HE As,with average diameters of 15.80 nm,37.09 nm,and 62.50 nm,respectively.The average sizes of helium bubbles observed in samples after 673-K irradiation are 1.46 nm,1.65 nm,and 1.58 nm,respectively.The improvement in the irradiation resistance of FeCoNiCr(Ni_3Ti)_(0.1) HEAs is evidenced by the diminution in bubbles size.Furthermore,the FeCoNiCr(Ni_3Ti)_(0.1) HEAs containing γ' precipitates of 15.8 nm exhibits the minimum size and density of helium bubbles,which can be ascribed to the considerable helium trapping effects of heterogeneous coherent phase boundaries.Subsequently,annealing experiments conducted after 293-K irradiation indicate that HEAs containing precipitated phases exhibits smaller apparent activation energy(E_a) for helium bubbles,resulting in larger helium bubble size.This study provides guidance for improving the irradiation resistance of L1_2-strengthened high-entropy alloy.展开更多
Since the superior mechanical,chemical and physical properties of high-entropy alloys(HEAs)were discovered,they have gradually become new emerging candidates for renewable energy applications.This review presents the ...Since the superior mechanical,chemical and physical properties of high-entropy alloys(HEAs)were discovered,they have gradually become new emerging candidates for renewable energy applications.This review presents the novel applications of HEAs in thermoelectric energy conversion.Firstly,the basic concepts and structural properties of HEAs are introduced.Then,we discuss a number of promising thermoelectric materials based on HEAs.Finally,the conclusion and outlook are presented.This article presents an advanced understanding of the thermoelectric properties of HEAs,which provides new opportunities for promoting their applications in renewable energy.展开更多
Specific grades of high-entropy alloys(HEAs)can provide opportunities for optimizing properties toward high-temperature applications.In this work,the Co-based HEA with a chemical composition of Co_(47.5)Cr_(30)Fe_(7.5...Specific grades of high-entropy alloys(HEAs)can provide opportunities for optimizing properties toward high-temperature applications.In this work,the Co-based HEA with a chemical composition of Co_(47.5)Cr_(30)Fe_(7.5)Mn_(7.5)Ni_(7.5)(at%)was chosen.The refractory metallic elements hafnium(Hf)and molybdenum(Mo)were added in small amounts(1.5at%)because of their well-known positive effects on high-temperature properties.Inclusion characteristics were comprehensively explored by using a two-dimensional cross-sectional method and extracted by using a three-dimensional electrolytic extraction method.The results revealed that the addition of Hf can reduce Al_(2)O_(3)inclusions and lead to the formation of more stable Hf-rich inclusions as the main phase.Mo addition cannot influence the inclusion type but could influence the inclusion characteristics by affecting the physical parameters of the HEA melt.The calculated coagulation coefficient and collision rate of Al_(2)O_(3)inclusions were higher than those of HfO_(2)inclusions,but the inclusion amount played a larger role in the agglomeration behavior of HfO_(2)and Al_(2)O_(3)inclusions.The impurity level and active elements in HEAs were the crucial factors affecting inclusion formation.展开更多
High entropy alloys(HEAs)have excellent application prospects in catalysis because of their rich components and configuration space.In this work,we develop a Bayesian neural network(BNN)based on energies calculated wi...High entropy alloys(HEAs)have excellent application prospects in catalysis because of their rich components and configuration space.In this work,we develop a Bayesian neural network(BNN)based on energies calculated with density functional theory to search the configuration space of the CoNiRhRu HEA system.The BNN model was developed by considering six independent features of Co-Ni,Co-Rh,CoRu,Ni-Rh,Ni-Ru,and Rh-Ru in different shells and energies of structures as the labels.The root mean squared error of the energy predicted by BNN is 1.37 me V/atom.Moreover,the influence of feature periodicity on the energy of HEA in theoretical calculations is discussed.We found that when the neural network is optimized to a certain extent,only using the accuracy indicator of root mean square error to evaluate model performance is no longer accurate in some scenarios.More importantly,we reveal the importance of uncertainty quantification for neural networks to predict new structures of HEAs with proper confidence based on BNN.展开更多
Sulfur element possesses an ultrahigh theoretical specific capacity,while the utilization of sulfur in the whole cathode is lower obviously owing to the sluggish kinetics of sulfur and discharged products,limiting the...Sulfur element possesses an ultrahigh theoretical specific capacity,while the utilization of sulfur in the whole cathode is lower obviously owing to the sluggish kinetics of sulfur and discharged products,limiting the enhancement on energy density of lithium-sulfur batteries.Herein,for the first time,Fe_(0.24)Co_(0.26)Ni_(0.10)Cu_(0.15)Mn_(0.25)high-entropy alloy is introduced as the core catalytic host to activate the electrochemical performance of the sulfur cathode for lithium-sulfur batteries.It is manifested that Fe_(0.24)Co_(0.26)Ni_(0.10)Cu_(0.15)Mn_(0.25)high-entropy alloy nanocrystallites distributed on nitrogen-doped carbon exhibit high electrocatalytic activity toward the conversion of solid sulfur to solid discharged products across soluble intermediate lithium polysulfides.In particular,benefiting from the accelerated kinetics by high-entropy alloy nanocrystallites and synergistic adsorption by nitrogen-doped carbon,the cathode exhibits high reversible capacity of 1079.5 mAh g_(-cathode)^(-1)(high utilization of 89.4%)with the whole cathode as active material,instead of sulfur element.Moreover,under both lean electrolyte(3μmg^(-1))and ultrahigh sulfur loading(27.0 mg cm^(-2))condition,the high discharge capacity of 868.2 mAh g_(-cathode)^(-1)can be still achieved for the sulfur cathode.This strategy opens up a new path to explore catalytic host materials for enhancing the utilization of sulfur in the whole cathode for lithium-sulfur batteries.展开更多
This study aimed to investigate the microstructure and mechanical properties of TixZrVNb(x=1,1.5,2)refractory high-entropy alloys at room and elevated temperatures.The TiZrVNb alloy consisted of the body-centered cubi...This study aimed to investigate the microstructure and mechanical properties of TixZrVNb(x=1,1.5,2)refractory high-entropy alloys at room and elevated temperatures.The TiZrVNb alloy consisted of the body-centered cubic(bcc)matrix with a small amount of V2Zr phase.The Ti1.5ZrVNb and Ti2ZrVNb alloys exhibited a single-phase bcc structure.At room temperature,the tensile ductility of the as-cast alloys increased from 3.5%to 12.3%with the increase in the Ti content.The TixZrVNb alloys exhibited high yield strength at 600°C,and the ultimate yield strength was more than 900 MPa.Softening occurred at 800°C,but the ultimate yield strength could still exceed 200 MPa.Moreover,the TixZrVNb alloys displayed low densities but high specific yield strengths(SYSs).The lowest density of TixZrVNb alloys was only 6.12 g/cm^3,but the SYS could reach about 180 MPa·cm^3·g^−1,which is better than those of most reported high-entropy alloys(HEAs).展开更多
There have been many interesting studies on high-entropy alloys(HEAs), also known as multi-component(MC) alloys(MCAs), in recent years. MC metallic-glasses(MGs) have shown the potential to express the advantag...There have been many interesting studies on high-entropy alloys(HEAs), also known as multi-component(MC) alloys(MCAs), in recent years. MC metallic-glasses(MGs) have shown the potential to express the advantages of MCAs and MGs in tandem. Amorphous phase formation rules are a crucial issue in the HEA and MCA field. For equal or near-equal atomic ratio alloys, mixed-entropy among the elements has a significant effect on the phase formation. This paper focuses on HEA amorphous phase formation rules. In the first two sections, the recent progress in amorphous phase formation in HEAs and MCAs is reviewed, including the effective factors and correlative parameters related to amorphous phase formation. In the third section, novel MCMGs including high-entropy(HE) bulk-metallic-glass(HE-BMG) and MCMG films developed in recent decades are summarized, and the giant-magnetic-impedance(GMI) effect of MC amorphous fibers is discussed.展开更多
Tribology,which is the study of friction,wear,and lubrication,largely deals with the service performance of structural materials.For example,newly emerging high-entropy alloys(HEAs),which exhibit excellent hardness,an...Tribology,which is the study of friction,wear,and lubrication,largely deals with the service performance of structural materials.For example,newly emerging high-entropy alloys(HEAs),which exhibit excellent hardness,anti-oxidation,anti-softening ability,and other prop-erties,enrich the wear-resistance alloy family.To demonstrate the tribological behavior of HEAs systematically,this review first describes the basic tribological characteristics of single-,dual-,and multi-phase HEAs and HEA composites at room temperature.Then,it summarizes the strategies that improve the tribological property of HEAs.This review also discusses the tribological performance at elevated temperatures and provides a brief perspective on the future development of HEAs for tribological applications.展开更多
The evolution of the microstructure and tensile properties of dual-phase Al0.6CoCrFeNi high-entropy alloys(HEAs)subjected to cold rolling was investigated.The homogenized Al0.6CoCrFeNi alloys consisted of face-centere...The evolution of the microstructure and tensile properties of dual-phase Al0.6CoCrFeNi high-entropy alloys(HEAs)subjected to cold rolling was investigated.The homogenized Al0.6CoCrFeNi alloys consisted of face-centered-cubic and body-centered-cubic phases,presenting similar mechanical behavior as the as-cast state.The yield and tensile strengths of the alloys could be dramatically enhanced to^1205 MPa and^1318 MPa after 50%rolling reduction,respectively.A power-law relationship was discovered between the strain-hardening exponent and rolling reduction.The tensile strengths of this dual-phase HEA with different cold rolling treatments were predicted,mainly based on the Hollomon relationship,by the strain-hardening exponent,and showed good agreement with the experimental results.展开更多
We prepared(CuCoFeNi)Tix(x=0,0.2,0.4,0.6,0.8,and 1.0)high-entropy alloys(HEAs)by vacuum arc melting and then investigated the effects of Ti on their microstructure and mechanical properties.When x was inreased to 0.6,...We prepared(CuCoFeNi)Tix(x=0,0.2,0.4,0.6,0.8,and 1.0)high-entropy alloys(HEAs)by vacuum arc melting and then investigated the effects of Ti on their microstructure and mechanical properties.When x was inreased to 0.6,the structure of the alloy transformed from their initial single face-centered cubic(fcc)structure into fcc+Laves mixed structure.The Laves phase was found to comprise Fe2Ti and be mainly distributed in the dendrite region.With increasing Ti content,both the Laves phase and the hardness of the alloy increased,whereas its yield and fracture strengths first increased and then decreased,reaching their highest value when x was 0.8.The(CuCoFeNi)Ti0.8 alloy exhibited the best overall mechanical properties,with yield and fracture strengths of 949.7 and 1723.4 MPa,respectively,a fracture strain of 27.92%,and a hardness of HV 461.6.展开更多
Using thermochemical treatments,boronized layers were successfully prepared on Al0.25CoCrFeNi high-entropy alloys(HEAs).The thickness of the boronized layers ranged widely from 20 to 50μm,depending on the heat treatm...Using thermochemical treatments,boronized layers were successfully prepared on Al0.25CoCrFeNi high-entropy alloys(HEAs).The thickness of the boronized layers ranged widely from 20 to 50μm,depending on the heat treatment time.Boronizing remarkably improved the surface hardness from HV 188 to HV 1265 after treating at 900°C for 9 h.Moreover,boronizing enhanced the yield strength of HEAs from 195 to 265 MPa but deteriorated the tensile ductility.Multiple crackings in the boride layers significantly decreased the plasticity.The insufficient work-hardening capacity essentially facilitated the plastic instability of the boronized HEAs.With decreasing substrate thickness,the fracture modes gradually transformed from dimples to quasi-cleavage and eventually to cleavage.展开更多
Developing megahertz(MHz)electromagnetic wave(EMW)absorption materials with broadband absorption,multi-temperature adaptability,and facile preparation method remains a challenge.Herein,nanocrystalline FeCoNiCr_(0.4)Cu...Developing megahertz(MHz)electromagnetic wave(EMW)absorption materials with broadband absorption,multi-temperature adaptability,and facile preparation method remains a challenge.Herein,nanocrystalline FeCoNiCr_(0.4)Cu_(0.2) high-entropy alloy powders(HEAs)with both large aspect ratios and thin intergranular amorphous layers are constructed by a multistage mechanical alloying strategy,aiming to achieve excellent and temperature-stable permeability and EMW absorption.A single-phase face-centered cubic structure with good ductility and high crystallinity is obtained as wet milling precursors,via precisely controlling dry milling time.Then,HEAs are flattened to improve aspect ratios by synergistically regulating wet milling time.FeCoNiCr_(0.4)Cu_(0.2) HEAs with dry milling 20 h and wet milling 5 h(D20)exhibit higher and more stable permeability because of larger aspect ratios and thinner intergranular amorphous layers.The maximum reflection loss(RL)of D20/SiO_(2) composites is greater than-7 dB with 5 mm thickness,and EMW absorption bandwidth(RL<-7 dB)can maintain between 523 and 600 MHz from-50 to 150℃.Furthermore,relying on the“cocktail effect”of HEAs,D20 sample also exhibits excellent corrosion resistance and high Curie temperature.This work provides a facile and tunable strategy to design MHz electromagnetic absorbers with temperature stability,broadband,and resistance to harsh environments.展开更多
A new method of high-gravity combustion synthesis(HGCS)followed by post-treatment(PT)is reported for preparing high-performance high-entropy alloys(HEAs),Cr0.9FeNi2.5V0.2Al0.5 alloy,whereby cheap thermite powder is us...A new method of high-gravity combustion synthesis(HGCS)followed by post-treatment(PT)is reported for preparing high-performance high-entropy alloys(HEAs),Cr0.9FeNi2.5V0.2Al0.5 alloy,whereby cheap thermite powder is used as the raw material.In this process,the HEA melt and the ceramic melt are rapidly formed by a strong exothermic combustion synthesis reaction and completely separated under a high-gravity field.Then,the master alloy is obtained after cooling.Subsequently,the master alloy is sequentially subjected to conventional vacuum arc melting(VAM),homogenization treatment,cold rolling,and annealing treatment to realize a tensile strength,yield strength,and elongation of 1250 MPa,1075 MPa,and 2.9%,respectively.The present method is increasingly attractive due to its low cost of raw materials and the intermediate product obtained without high-temperature heating.Based on the calculation of phase separation kinetics in the high-temperature melt,it is expected that the final alloys with high performance can be prepared directly across master alloys with higher high-gravity coefficients.展开更多
New refractory high-entropy alloys,CrHfNbTaTi and CrHfMoTaTi,derived from the well-known HfNbTaTiZr alloy through principal element substitution were prepared using vacuum arc melting.The phase components,microstructu...New refractory high-entropy alloys,CrHfNbTaTi and CrHfMoTaTi,derived from the well-known HfNbTaTiZr alloy through principal element substitution were prepared using vacuum arc melting.The phase components,microstructures,and compressive properties of the alloys in the as-cast state were investigated.Results showed that both alloys were composed of BCC and cubic Laves phases.In terms of mechanical properties,the yield strength increased remarkably from 926 MPa for HfNbTaTiZr to 1258 MPa for CrHfNbTaTi,whereas a promising plastic strain of around 15.0%was retained in CrHfNbTaTi.The morphology and composition of the network-shaped interdendritic regions were closely related to the improved mechanical properties due to elemental substitution.Dendrites were surrounded by an incompact interdendritic shell after Mo incorporation,which deteriorated yield strength and accelerated brittleness.展开更多
High-entropy alloys(HEAs)have attracted increasing attention because of their unique properties,including high strength,hardness,chemical stability,and good wear resistance.Powder metallurgy is one of the most importa...High-entropy alloys(HEAs)have attracted increasing attention because of their unique properties,including high strength,hardness,chemical stability,and good wear resistance.Powder metallurgy is one of the most important methods used to fabricate HEA materials.This paper introduces the methods used to synthesize HEA powders and consolidate HEA bulk.The phase transformation,microstructural evolution,and mechanical properties of HEAs obtained by powder metallurgy are summarized.We also address HEA-related materials such as ceramic–HEA cermets and HEA-based composites fabricated by powder metallurgy.展开更多
High-entropy alloys(HEAs)are based on solid solutions which characterized by chemical short-range ordering(CSRO),but there is no accurate structural tool to address CSRO characteristic,which obstacles precise composit...High-entropy alloys(HEAs)are based on solid solutions which characterized by chemical short-range ordering(CSRO),but there is no accurate structural tool to address CSRO characteristic,which obstacles precise composition design for HEAs.In this study,based on the cluster-plus-glue-atoms model,the composition law of Al-TMs(TMs,transition metals)HEAs with BCC and FCC structures was revealed.In BCC structure,with five elements in equi-atomic ratio,the composition formula of Al-TMs HEAs can be expressed by a cluster formula[Al-M_(14)]Al_(3),and in non equi-atomic ratio can be expressed by[Al-M_(14)]Al,where M is the average atom of the TMs.But in FCC structure,both Al-TMs HEAs with five elements in equiatomic and non equi-atomic ratios can be expressed by a cluster formula[Al-M_(12)]Al.To confirm the effectiveness of cluster formula for Al-TMs,two alloys were designed,[Al-Ti_(4)V_(3)Nb_(4)Mo_(3)]Mo and[Al-Ti_(3)V_(3)Nb_(4)Mo_(4)]Al.Results show that the[Al-Ti_(3)V_(3)Nb_(4)Mo_(4)]Al alloy has both higher strength and higher plastic deformation at room temperature.Besides,[Al-Ti_(3)V_(3)Nb_(4)Mo_(4)]Al alloy shows slower soften effect at 800℃,contributed to its higher strength.By substituting Ta for some of Mo,the strength of[Al-Ti_(3)V_(3)Nb_(4)Mo_(3)Ta]Al at room temperature and high temperature drastically decreases,suggesting that Ta element deteriorates the properties of Al-TMs alloys.展开更多
The enhancement of near-field radiative heat transfer(NFRHT)has now become one of the research hotspots in the fieldsof thermal management and imaging due to its ability to improve the performance of near-field thermo...The enhancement of near-field radiative heat transfer(NFRHT)has now become one of the research hotspots in the fieldsof thermal management and imaging due to its ability to improve the performance of near-field thermoelectric devices and near-field imaging systems.In this paper,we design three structures(multilayer structure,nanoporous structure,and nanorod structure)based on high-entropy alloys to realize the enhancement of NFRHT.By combining stochastic electrodynamicsand Maxwell-Garnett's description of the effective medium,we calculate the radiative heat transfer under different parametersand find that the nanoporousstructure has the largest enhancement effect on NFRHT.The near-field heat transfer factor(q)of this structure(q=1.40×10^(9)W/(m^(2)·K))is three times higher than that of the planestructure(q=4.6×10^(8)W/(m^(2)·K)),and about two orders of magnitude higher than that of the SiO2plate.Thisresult providesa freshidea for the enhancement of NFRHT and will promote the application of high-entropy alloy materials in near-field heat radiation.展开更多
High-temperature oxidation is a common failure in high-temperature environments,which widely occur in aircraft engines and aerospace thrusters;as a result,the development of anti-high-temperature oxidation materials h...High-temperature oxidation is a common failure in high-temperature environments,which widely occur in aircraft engines and aerospace thrusters;as a result,the development of anti-high-temperature oxidation materials has been pursued.Ni-based alloys are a common high-temperature material;however,they are too expensive.High-entropy alloys are alternatives for the anti-oxidation property at high temperatures because of their special structure and properties.The recent achievements of high-temperature oxidation are reviewed in this paper.The high-temperature oxidation environment,temperature,phase structure,alloy elements,and preparation methods of high-entropy alloys are summarized.The reason why high-entropy alloys have anti-oxidation ability at high temperatures is illuminated.Current research,material selection,and application prospects of high-temperature oxidation are introduced.展开更多
基金supported by the National Natural Science Foundation of China(No.52273280)the Creative Research Groups of China(No.51921001).
文摘High-entropy alloys(HEAs),which were introduced as a pioneering concept in 2004,have captured the keen interest of nu-merous researchers.Entropy,in this context,can be perceived as representing disorder and randomness.By contrast,elemental composi-tions within alloy systems occupy specific structural sites in space,a concept referred to as structure.In accordance with Shannon entropy,structure is analogous to information.Generally,the arrangement of atoms within a material,termed its structure,plays a pivotal role in dictating its properties.In addition to expanding the array of options for alloy composites,HEAs afford ample opportunities for diverse structural designs.The profound influence of distinct structural features on the exceptional behaviors of alloys is underscored by numer-ous examples.These features include remarkably high fracture strength with excellent ductility,antiballistic capability,exceptional radi-ation resistance,and corrosion resistance.In this paper,we delve into various unique material structures and properties while elucidating the intricate relationship between structure and performance.
基金supported by the Office of Scientific Research of Shandong Vocational and Technical University of International Studies.
文摘This review focuses on thermodynamic and physical parameters,synthesis methods,and reported phases of Magnesium(Mg)containing high-entropy alloys(HEAs).Statistical data of publications concerning Mg-containing HEAs were collected and analyzed.Data on the chemical elements included in Mg-containing HEAs,their theoretical end experimental densities,thermodynamic parameters,physical parameters,fabricated techniques and reported phases were also collected and discussed.On the basis of this information,a new classification for HEAs was proposed.It is also shown that the existing thermodynamic parameters cannot accurately predict the formation of a single phase solid solution for Mg-containing HEAs.The physical parameters of Mg-containing HEAs are within a wide range,and most of the synthesized Mg-containing HEAs have a complex multiphase structure.
基金Project support provided by the National Natural Science Foundation of China(Grant No.12075200)the National Key Research and Development Program of China(Grant No.2022YFB3706004)。
文摘A series of high-entropy alloys(HEAs) containing nanoprecipitates of varying sizes is successfully prepared by a non-consuming vacuum arc melting method.In order to study the irradiation evolution of helium bubbles in the FeCoNiCrbased HE As with γ' precipitates,these samples are irradiated by 100-keV helium ions with a fluence of 5 × 10~(20) ions/m~2 at 293 K and 673 K,respectively.And the samples irradiated at room temperature are annealed at different temperatures to examine the diffusion behavior of helium bubbles.Transmission electron microscope(TEM) is employed to characterize the structural morphology of precipitated nanoparticles and the evolution of helium bubbles.Experimental results reveal that nanosized,spherical,dispersed,coherent,and ordered L1_2-type Ni_3Ti γ' precipitations are introduced into FeCoNiCr(Ni_3Ti)_(0.1) HEAs by means of ageing treatments at temperatures between 1073 K and 1123 K.Under the ageing treatment conditions adopted in this work,γ' nanoparticles are precipitated in FeCoNiCr(Ni_3Ti)_(0.1) HE As,with average diameters of 15.80 nm,37.09 nm,and 62.50 nm,respectively.The average sizes of helium bubbles observed in samples after 673-K irradiation are 1.46 nm,1.65 nm,and 1.58 nm,respectively.The improvement in the irradiation resistance of FeCoNiCr(Ni_3Ti)_(0.1) HEAs is evidenced by the diminution in bubbles size.Furthermore,the FeCoNiCr(Ni_3Ti)_(0.1) HEAs containing γ' precipitates of 15.8 nm exhibits the minimum size and density of helium bubbles,which can be ascribed to the considerable helium trapping effects of heterogeneous coherent phase boundaries.Subsequently,annealing experiments conducted after 293-K irradiation indicate that HEAs containing precipitated phases exhibits smaller apparent activation energy(E_a) for helium bubbles,resulting in larger helium bubble size.This study provides guidance for improving the irradiation resistance of L1_2-strengthened high-entropy alloy.
基金Project supported by the Natural Science Foundation of Jiangsu Province of China(Grant Nos.BK20220407 and BK20220428)。
文摘Since the superior mechanical,chemical and physical properties of high-entropy alloys(HEAs)were discovered,they have gradually become new emerging candidates for renewable energy applications.This review presents the novel applications of HEAs in thermoelectric energy conversion.Firstly,the basic concepts and structural properties of HEAs are introduced.Then,we discuss a number of promising thermoelectric materials based on HEAs.Finally,the conclusion and outlook are presented.This article presents an advanced understanding of the thermoelectric properties of HEAs,which provides new opportunities for promoting their applications in renewable energy.
基金the Swedish Foundation for International Cooperation in Research and Higher Education(STINT,Nos.IB2020-8781 and IB20229228)for the collaboration between KTH<U(Sweden),HYU(Korea),and NEU(China)VINNOVA(No.2022-01216),the SSF Strategic Mobility Grant(No.SM22-0039),the?Forsk(No.23-540),and the Swedish Steel Producers’Association(Jernkontoret),in particular,Axel Ax:-son Johnsons forskningsfond,Prytziska fondennr 2,Gerhard von Hofstens Stiftelse f?r Metallurgisk forskning,and Stiftelsen?veringenj?ren Gustaf Janssons Jernkontorsfond for the financial support.Key Lab of EPM(NEU)is acknowledged for supporting the partial FactSage calculation+2 种基金the Key Laboratory for Ferrous Metallurgy and Resources Utilization of the Min-istry of Education and Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking(No.FMRUlab-22-1)for supporting this researchThe Natural Science Foundation of Liaoning Province,China(No.2023MSBA-135)the Fundamental Research Funds for the Central Universities(No.N2409006)are also acknowledged。
文摘Specific grades of high-entropy alloys(HEAs)can provide opportunities for optimizing properties toward high-temperature applications.In this work,the Co-based HEA with a chemical composition of Co_(47.5)Cr_(30)Fe_(7.5)Mn_(7.5)Ni_(7.5)(at%)was chosen.The refractory metallic elements hafnium(Hf)and molybdenum(Mo)were added in small amounts(1.5at%)because of their well-known positive effects on high-temperature properties.Inclusion characteristics were comprehensively explored by using a two-dimensional cross-sectional method and extracted by using a three-dimensional electrolytic extraction method.The results revealed that the addition of Hf can reduce Al_(2)O_(3)inclusions and lead to the formation of more stable Hf-rich inclusions as the main phase.Mo addition cannot influence the inclusion type but could influence the inclusion characteristics by affecting the physical parameters of the HEA melt.The calculated coagulation coefficient and collision rate of Al_(2)O_(3)inclusions were higher than those of HfO_(2)inclusions,but the inclusion amount played a larger role in the agglomeration behavior of HfO_(2)and Al_(2)O_(3)inclusions.The impurity level and active elements in HEAs were the crucial factors affecting inclusion formation.
基金supported by the Shanghai Rising-Star Program (20QA1406800)the National Natural Science Foundation of China (22072091,91745102,92045301)。
文摘High entropy alloys(HEAs)have excellent application prospects in catalysis because of their rich components and configuration space.In this work,we develop a Bayesian neural network(BNN)based on energies calculated with density functional theory to search the configuration space of the CoNiRhRu HEA system.The BNN model was developed by considering six independent features of Co-Ni,Co-Rh,CoRu,Ni-Rh,Ni-Ru,and Rh-Ru in different shells and energies of structures as the labels.The root mean squared error of the energy predicted by BNN is 1.37 me V/atom.Moreover,the influence of feature periodicity on the energy of HEA in theoretical calculations is discussed.We found that when the neural network is optimized to a certain extent,only using the accuracy indicator of root mean square error to evaluate model performance is no longer accurate in some scenarios.More importantly,we reveal the importance of uncertainty quantification for neural networks to predict new structures of HEAs with proper confidence based on BNN.
基金Financial support from National Natural Science Foundation of China(21935006)is gratefully acknowledged。
文摘Sulfur element possesses an ultrahigh theoretical specific capacity,while the utilization of sulfur in the whole cathode is lower obviously owing to the sluggish kinetics of sulfur and discharged products,limiting the enhancement on energy density of lithium-sulfur batteries.Herein,for the first time,Fe_(0.24)Co_(0.26)Ni_(0.10)Cu_(0.15)Mn_(0.25)high-entropy alloy is introduced as the core catalytic host to activate the electrochemical performance of the sulfur cathode for lithium-sulfur batteries.It is manifested that Fe_(0.24)Co_(0.26)Ni_(0.10)Cu_(0.15)Mn_(0.25)high-entropy alloy nanocrystallites distributed on nitrogen-doped carbon exhibit high electrocatalytic activity toward the conversion of solid sulfur to solid discharged products across soluble intermediate lithium polysulfides.In particular,benefiting from the accelerated kinetics by high-entropy alloy nanocrystallites and synergistic adsorption by nitrogen-doped carbon,the cathode exhibits high reversible capacity of 1079.5 mAh g_(-cathode)^(-1)(high utilization of 89.4%)with the whole cathode as active material,instead of sulfur element.Moreover,under both lean electrolyte(3μmg^(-1))and ultrahigh sulfur loading(27.0 mg cm^(-2))condition,the high discharge capacity of 868.2 mAh g_(-cathode)^(-1)can be still achieved for the sulfur cathode.This strategy opens up a new path to explore catalytic host materials for enhancing the utilization of sulfur in the whole cathode for lithium-sulfur batteries.
基金the National Magnetic Confinement Fusion Energy R&D Program(No.2018YFE0312400)the National Natural Science Foundation of China(Nos.51822402 and 51671044)+3 种基金the National Key Research and Development Program of China(Nos.019YFA0209901 and 2018YFA0702901)the Fund of the State Key Laboratory of Solidification Processing in Northwestern Polytechnical University(Grant No.SKLSP201902)the Liaoning Revitalization Talents Program(No.XLYC1807047)the Fund of Science and Technology on Reactor Fuel and Materials Laboratory(No.STRFML-2020-04).
文摘This study aimed to investigate the microstructure and mechanical properties of TixZrVNb(x=1,1.5,2)refractory high-entropy alloys at room and elevated temperatures.The TiZrVNb alloy consisted of the body-centered cubic(bcc)matrix with a small amount of V2Zr phase.The Ti1.5ZrVNb and Ti2ZrVNb alloys exhibited a single-phase bcc structure.At room temperature,the tensile ductility of the as-cast alloys increased from 3.5%to 12.3%with the increase in the Ti content.The TixZrVNb alloys exhibited high yield strength at 600°C,and the ultimate yield strength was more than 900 MPa.Softening occurred at 800°C,but the ultimate yield strength could still exceed 200 MPa.Moreover,the TixZrVNb alloys displayed low densities but high specific yield strengths(SYSs).The lowest density of TixZrVNb alloys was only 6.12 g/cm^3,but the SYS could reach about 180 MPa·cm^3·g^−1,which is better than those of most reported high-entropy alloys(HEAs).
基金supported by the National Natural Science Foundation of China(Grant No.51471025)
文摘There have been many interesting studies on high-entropy alloys(HEAs), also known as multi-component(MC) alloys(MCAs), in recent years. MC metallic-glasses(MGs) have shown the potential to express the advantages of MCAs and MGs in tandem. Amorphous phase formation rules are a crucial issue in the HEA and MCA field. For equal or near-equal atomic ratio alloys, mixed-entropy among the elements has a significant effect on the phase formation. This paper focuses on HEA amorphous phase formation rules. In the first two sections, the recent progress in amorphous phase formation in HEAs and MCAs is reviewed, including the effective factors and correlative parameters related to amorphous phase formation. In the third section, novel MCMGs including high-entropy(HE) bulk-metallic-glass(HE-BMG) and MCMG films developed in recent decades are summarized, and the giant-magnetic-impedance(GMI) effect of MC amorphous fibers is discussed.
基金the National Nat-ural Science Foundation of China(Nos.51901013,52071023,and 52122408)the State Key Lab of Advanced Metals and Materials(No.2020-Z16)the Fundamental Research Funds for the Central Universities(University of Science and Technology Beijing)(No.06500135).
文摘Tribology,which is the study of friction,wear,and lubrication,largely deals with the service performance of structural materials.For example,newly emerging high-entropy alloys(HEAs),which exhibit excellent hardness,anti-oxidation,anti-softening ability,and other prop-erties,enrich the wear-resistance alloy family.To demonstrate the tribological behavior of HEAs systematically,this review first describes the basic tribological characteristics of single-,dual-,and multi-phase HEAs and HEA composites at room temperature.Then,it summarizes the strategies that improve the tribological property of HEAs.This review also discusses the tribological performance at elevated temperatures and provides a brief perspective on the future development of HEAs for tribological applications.
基金the Natural Science Foundation of Shanxi Province,China(Nos.201901D111105 and 201901D111114)Transformation of Scientific and Technological Achievements Programs of Higher Education Institutions in Shanxi Province,China(2019)+2 种基金the Opening Project of the State Key Laboratory of Explosion Science and Technology(Beijing Institute of Technology)(No.KFJJ20-13M)the Graduate Science and Technology Innovation Fund Project of Shanxi Province,China(No.2019BY044)the State Key Lab of Advanced Metals and Materials of China(No.2020-Z09).
文摘The evolution of the microstructure and tensile properties of dual-phase Al0.6CoCrFeNi high-entropy alloys(HEAs)subjected to cold rolling was investigated.The homogenized Al0.6CoCrFeNi alloys consisted of face-centered-cubic and body-centered-cubic phases,presenting similar mechanical behavior as the as-cast state.The yield and tensile strengths of the alloys could be dramatically enhanced to^1205 MPa and^1318 MPa after 50%rolling reduction,respectively.A power-law relationship was discovered between the strain-hardening exponent and rolling reduction.The tensile strengths of this dual-phase HEA with different cold rolling treatments were predicted,mainly based on the Hollomon relationship,by the strain-hardening exponent,and showed good agreement with the experimental results.
基金the National Natural Science Foundation of China(Nos.51604161 and 51604162)Hubei Key Laboratory of Hydroelectric Machinery Design&Maintenance Program(No.2019KJX10).
文摘We prepared(CuCoFeNi)Tix(x=0,0.2,0.4,0.6,0.8,and 1.0)high-entropy alloys(HEAs)by vacuum arc melting and then investigated the effects of Ti on their microstructure and mechanical properties.When x was inreased to 0.6,the structure of the alloy transformed from their initial single face-centered cubic(fcc)structure into fcc+Laves mixed structure.The Laves phase was found to comprise Fe2Ti and be mainly distributed in the dendrite region.With increasing Ti content,both the Laves phase and the hardness of the alloy increased,whereas its yield and fracture strengths first increased and then decreased,reaching their highest value when x was 0.8.The(CuCoFeNi)Ti0.8 alloy exhibited the best overall mechanical properties,with yield and fracture strengths of 949.7 and 1723.4 MPa,respectively,a fracture strain of 27.92%,and a hardness of HV 461.6.
基金National Key Laboratory for Remanufacturing,Academy of Armored Forces Engineering(No.61420050204)the Transformation of Scientific and Technological Achievements Programs of Higher Education Institutions in Shanxi,China(No.2019BY044)Jinxiong Hou would like to acknowledge the financial support from the Graduate Science and Technology Innovation Fund Project of Shanxi,China(No.2019BY044).
文摘Using thermochemical treatments,boronized layers were successfully prepared on Al0.25CoCrFeNi high-entropy alloys(HEAs).The thickness of the boronized layers ranged widely from 20 to 50μm,depending on the heat treatment time.Boronizing remarkably improved the surface hardness from HV 188 to HV 1265 after treating at 900°C for 9 h.Moreover,boronizing enhanced the yield strength of HEAs from 195 to 265 MPa but deteriorated the tensile ductility.Multiple crackings in the boride layers significantly decreased the plasticity.The insufficient work-hardening capacity essentially facilitated the plastic instability of the boronized HEAs.With decreasing substrate thickness,the fracture modes gradually transformed from dimples to quasi-cleavage and eventually to cleavage.
基金the Supported by Program for the National Natural Science Foundation of China(No.52071053,U1704253,52103334)China Postdoctoral Science Foundation(2020M670748,2020M680946)the Fundamental Research Funds for the Central Universities(DUT20GF111).
文摘Developing megahertz(MHz)electromagnetic wave(EMW)absorption materials with broadband absorption,multi-temperature adaptability,and facile preparation method remains a challenge.Herein,nanocrystalline FeCoNiCr_(0.4)Cu_(0.2) high-entropy alloy powders(HEAs)with both large aspect ratios and thin intergranular amorphous layers are constructed by a multistage mechanical alloying strategy,aiming to achieve excellent and temperature-stable permeability and EMW absorption.A single-phase face-centered cubic structure with good ductility and high crystallinity is obtained as wet milling precursors,via precisely controlling dry milling time.Then,HEAs are flattened to improve aspect ratios by synergistically regulating wet milling time.FeCoNiCr_(0.4)Cu_(0.2) HEAs with dry milling 20 h and wet milling 5 h(D20)exhibit higher and more stable permeability because of larger aspect ratios and thinner intergranular amorphous layers.The maximum reflection loss(RL)of D20/SiO_(2) composites is greater than-7 dB with 5 mm thickness,and EMW absorption bandwidth(RL<-7 dB)can maintain between 523 and 600 MHz from-50 to 150℃.Furthermore,relying on the“cocktail effect”of HEAs,D20 sample also exhibits excellent corrosion resistance and high Curie temperature.This work provides a facile and tunable strategy to design MHz electromagnetic absorbers with temperature stability,broadband,and resistance to harsh environments.
基金the National Natural Science Foundation of China(No.51702332)the Key Research Projects in Gansu Province(No.17YF1GA020)the CAS Key Laboratory of Cryogenics,Technical Institute of Physics and Chemistry(Youth Innovation Fund No.CRYOQN201705).
文摘A new method of high-gravity combustion synthesis(HGCS)followed by post-treatment(PT)is reported for preparing high-performance high-entropy alloys(HEAs),Cr0.9FeNi2.5V0.2Al0.5 alloy,whereby cheap thermite powder is used as the raw material.In this process,the HEA melt and the ceramic melt are rapidly formed by a strong exothermic combustion synthesis reaction and completely separated under a high-gravity field.Then,the master alloy is obtained after cooling.Subsequently,the master alloy is sequentially subjected to conventional vacuum arc melting(VAM),homogenization treatment,cold rolling,and annealing treatment to realize a tensile strength,yield strength,and elongation of 1250 MPa,1075 MPa,and 2.9%,respectively.The present method is increasingly attractive due to its low cost of raw materials and the intermediate product obtained without high-temperature heating.Based on the calculation of phase separation kinetics in the high-temperature melt,it is expected that the final alloys with high performance can be prepared directly across master alloys with higher high-gravity coefficients.
基金supported by the National Natural Science Foundation of China(No.51604173)the Natural Science Foundation of Jiangsu Higher Education Institution of China(No.18KJB430012)。
文摘New refractory high-entropy alloys,CrHfNbTaTi and CrHfMoTaTi,derived from the well-known HfNbTaTiZr alloy through principal element substitution were prepared using vacuum arc melting.The phase components,microstructures,and compressive properties of the alloys in the as-cast state were investigated.Results showed that both alloys were composed of BCC and cubic Laves phases.In terms of mechanical properties,the yield strength increased remarkably from 926 MPa for HfNbTaTiZr to 1258 MPa for CrHfNbTaTi,whereas a promising plastic strain of around 15.0%was retained in CrHfNbTaTi.The morphology and composition of the network-shaped interdendritic regions were closely related to the improved mechanical properties due to elemental substitution.Dendrites were surrounded by an incompact interdendritic shell after Mo incorporation,which deteriorated yield strength and accelerated brittleness.
基金The authors are grateful to the National Key Research and Development Plan of China(No.2017YF130310400)the National Natural Science Foundation of China(Nos.51521001 and 51902233)+1 种基金the Self-determined and Innovative Research Funds of WHUT(Nos.2018III020 and 2018IVA094)the Students Innovation and Entrepreneurship Training Program of WHUT(Nos.2018CLA127 and 20181049701037).
文摘High-entropy alloys(HEAs)have attracted increasing attention because of their unique properties,including high strength,hardness,chemical stability,and good wear resistance.Powder metallurgy is one of the most important methods used to fabricate HEA materials.This paper introduces the methods used to synthesize HEA powders and consolidate HEA bulk.The phase transformation,microstructural evolution,and mechanical properties of HEAs obtained by powder metallurgy are summarized.We also address HEA-related materials such as ceramic–HEA cermets and HEA-based composites fabricated by powder metallurgy.
基金supported by the National Key Research and Development Program of China(Grant Nos.2020YFB2008305,2020YFB2008303).
文摘High-entropy alloys(HEAs)are based on solid solutions which characterized by chemical short-range ordering(CSRO),but there is no accurate structural tool to address CSRO characteristic,which obstacles precise composition design for HEAs.In this study,based on the cluster-plus-glue-atoms model,the composition law of Al-TMs(TMs,transition metals)HEAs with BCC and FCC structures was revealed.In BCC structure,with five elements in equi-atomic ratio,the composition formula of Al-TMs HEAs can be expressed by a cluster formula[Al-M_(14)]Al_(3),and in non equi-atomic ratio can be expressed by[Al-M_(14)]Al,where M is the average atom of the TMs.But in FCC structure,both Al-TMs HEAs with five elements in equiatomic and non equi-atomic ratios can be expressed by a cluster formula[Al-M_(12)]Al.To confirm the effectiveness of cluster formula for Al-TMs,two alloys were designed,[Al-Ti_(4)V_(3)Nb_(4)Mo_(3)]Mo and[Al-Ti_(3)V_(3)Nb_(4)Mo_(4)]Al.Results show that the[Al-Ti_(3)V_(3)Nb_(4)Mo_(4)]Al alloy has both higher strength and higher plastic deformation at room temperature.Besides,[Al-Ti_(3)V_(3)Nb_(4)Mo_(4)]Al alloy shows slower soften effect at 800℃,contributed to its higher strength.By substituting Ta for some of Mo,the strength of[Al-Ti_(3)V_(3)Nb_(4)Mo_(3)Ta]Al at room temperature and high temperature drastically decreases,suggesting that Ta element deteriorates the properties of Al-TMs alloys.
基金This work is supported by the National Natural Science Foundation of China(Grant Nos.52101233,51931007,and 52071279)the Hebei Natural Science Foundation(No.E2022203010)the Innovation Capability Improvement Project of Hebei Province(No.22567605H).
文摘The enhancement of near-field radiative heat transfer(NFRHT)has now become one of the research hotspots in the fieldsof thermal management and imaging due to its ability to improve the performance of near-field thermoelectric devices and near-field imaging systems.In this paper,we design three structures(multilayer structure,nanoporous structure,and nanorod structure)based on high-entropy alloys to realize the enhancement of NFRHT.By combining stochastic electrodynamicsand Maxwell-Garnett's description of the effective medium,we calculate the radiative heat transfer under different parametersand find that the nanoporousstructure has the largest enhancement effect on NFRHT.The near-field heat transfer factor(q)of this structure(q=1.40×10^(9)W/(m^(2)·K))is three times higher than that of the planestructure(q=4.6×10^(8)W/(m^(2)·K)),and about two orders of magnitude higher than that of the SiO2plate.Thisresult providesa freshidea for the enhancement of NFRHT and will promote the application of high-entropy alloy materials in near-field heat radiation.
基金This work was financially supported by the National Natural Science Foundation of China(No.52071014)the Fundamental Research Funds for the Central Universities(No.FRF-GF-19-033BZ)the National Key Research and Development Program of China(No.2020YFB0704501).
文摘High-temperature oxidation is a common failure in high-temperature environments,which widely occur in aircraft engines and aerospace thrusters;as a result,the development of anti-high-temperature oxidation materials has been pursued.Ni-based alloys are a common high-temperature material;however,they are too expensive.High-entropy alloys are alternatives for the anti-oxidation property at high temperatures because of their special structure and properties.The recent achievements of high-temperature oxidation are reviewed in this paper.The high-temperature oxidation environment,temperature,phase structure,alloy elements,and preparation methods of high-entropy alloys are summarized.The reason why high-entropy alloys have anti-oxidation ability at high temperatures is illuminated.Current research,material selection,and application prospects of high-temperature oxidation are introduced.