High entropy alloy attracts widespread attention due to its excellent mechanical properties.It becomes a new type of alloy material with high application potential,but the grinding performance of High entropy alloy re...High entropy alloy attracts widespread attention due to its excellent mechanical properties.It becomes a new type of alloy material with high application potential,but the grinding performance of High entropy alloy receives little attention.This paper conducts grinding simulation and surface grinding experiments on FeCoCrNi high entropy and alloys to analyze the grinding removal mechanism of the FeCoCrNi-based High entropy alloy.We also discuss the influence of grinding parameters,element types,element content and forming methods on grinding force and sub-surface plastic deformation after grinding.The simulation and experimental results show that as the increase of grinding depth,both tangential grinding force and normal grinding force increase,and the thickness of sub-surface plastic deformation layer decreases.With the increase of grinding speed,both tangential grinding force and normal grinding force decrease,and the thickness of sub-surface plastic deformation layer caused by grinding process shows a trend of gradual decrease.Under the same processing parameters,the normal grinding force is greater than the tangential grinding force.In FeCoCrNi series high entropy alloys,the grinding force and subsurface plastic deformation layer thickness of high entropy alloys increased with the addition in Ti content.The grinding force and plastic deformation formed by adding Ti element are greater than those formed by adding Al element,and High entropy alloys prepared using laser cladding method exhibit greater grinding force and plastic deformation than those prepared using selective laser melting method.The research results provide theoretical reference and experimental basis for high-quality grinding of high entropy alloys,which may be helpful for the design and manufacturing of high entropy alloy parts.展开更多
High entropy alloys(HEAs)have recently attracted significant attention due to their exceptional mechanical properties and potential applications across various fields.Friction stir welding and processing(FSW/P),as not...High entropy alloys(HEAs)have recently attracted significant attention due to their exceptional mechanical properties and potential applications across various fields.Friction stir welding and processing(FSW/P),as notable solid-state welding and processing techniques,have been proved effectiveness in enhancing microstructures and mechanical properties of HEAs.This review article summarizes the current status of FSW/P of HEAs.The welding materials and conditions used for FSW/P in HEAs are reviewed and discussed.The effects of FSW/P on the evolutions of grain structure,texture,dislocation,and secondary phase for different HEAs are highlighted.Furthermore,the influences of FSW/P on the mechanical properties of various HEAs are analyzed.Finally,potential applications,challenges,and future directions of FSW/P in HEAs are forecasted.Overall,FSW/P enable to refine grains of HEAs through dynamic recrystallization and to activate diverse deformation mechanisms of HEAs through tailoring phase structures,thereby significantly improving the strength,hardness,and ductility of both single-and dual-phase HEAs.Future progress in this field will rely on comprehensive optimization of processing parameters and alloy composition,integration of multi-scale modeling with advanced characterization for in-depth exploration of microstructural mechanisms,systematic evaluation of functional properties,and effective bridging of the gap between laboratory research and industrial application.The review aims to provide an overview of recent advancements in the FSW/P of HEAs and encourage further research in this area.展开更多
Reversible solid oxide cell(RSOC)is a new energy conversion device with significant applications,especially for power grid peaking shaving.However,the reversible conversion process of power generation/energy storage p...Reversible solid oxide cell(RSOC)is a new energy conversion device with significant applications,especially for power grid peaking shaving.However,the reversible conversion process of power generation/energy storage poses challenges for the performance and stability of air electrodes.In this work,a novel high-entropy perovskite oxide La_(0.2)Pr_(0.2)Gd_(0.2)Sm_(0.2)Sr_(0.2)Co_(0.8)Fe_(0.2)O_(3−δ)(HE-LSCF)is proposed and investigated as an air electrode in RSOC.The electrochemical behavior of HE-LSCF was studied as an air electrode in both fuel cell and electrolysis modes.The polarization impedance(Rp)of the HE-LSCF electrode is only 0.25Ω·cm^(2) at 800℃ in an air atmosphere.Notably,at an electrolytic voltage of 2 V and a temperature of 800℃,the current density reaches up to 1.68 A/cm^(2).The HE-LSCF air electrode exhibited excellent reversibility and stability,and its electrochemical performance remains stable after 100 h of reversible operation.With these advantages,HE-LSCF is shown to be an excellent air electrode for RSOC.展开更多
Up-and-coming high-temperature materials,refractory high entropy alloys,are suffering from lower oxidation resistance,restricting their applications in the aerospace field.In this study,two novel treatments of Al-depo...Up-and-coming high-temperature materials,refractory high entropy alloys,are suffering from lower oxidation resistance,restricting their applications in the aerospace field.In this study,two novel treatments of Al-deposited and remelted were developed to refine the microstructure and enhance the oxidation resistance of refractory high entropy alloy using electron beam freeform fabrication(EBF3).Finer and short-range ordering structures were observed in the remelted sample,whereas the Al-deposited sample showcased the formation of silicide and intermetallic phases.High-temperature cyclic and isothermal oxidation tests at 1000℃ were carried out.The total weight gain after 60 h of cyclic oxidation decreased by 17.49%and 30.46%for the remelted and deposited samples,respectively,compared to the as-cast state.Oxidation kinetics reveal an evident lower mass gain and oxidation rate in the treated samples.A multilayer oxide consisting of TiO_(2)+Al_(2)O_(3)+SiO_(2)+AlNbO_(4) was studied for its excellent oxidation resistance.The oxidation behavior of rutile,corundum and other oxides was analyzed using first principles calculations and chemical defect analysis.Overall,this research,which introduces novel treatments,offers promising insights for enhancing the inherent oxidation resistance of refractory high entropy alloys.展开更多
Low thermal conductivity and excellent mechanical strength are essential to pyrochlore A2B2O7 ceramic for environmental/thermal barrier coating applications.To collaboratively tailor the mechanical and thermal propert...Low thermal conductivity and excellent mechanical strength are essential to pyrochlore A2B2O7 ceramic for environmental/thermal barrier coating applications.To collaboratively tailor the mechanical and thermal properties of A2B2O7 ceramic,a novel high entropy pyrochlore ceramic(La_(0.3)Gd_(0.3)Ca_(0.4))_(2)(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))_(2)O_(7) with significant atomic radius and mass fluctuation is proposed by simultaneously introducing various elements with different valence states at A and B cation sites.The as-synthesized(La_(0.3)Gd_(0.3)Ca_(0.4))_(2)(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))_(2)O_(7) exhibits enhanced fracture toughness(1.68 MPa m^(1/2)),amorphous-like low thermal conductivity(1.45 W m^(-1) K^(-1) at 900℃)and matched thermal expansion coefficient(9.0×10^(-6) K^(-1) at 1200℃)with Al_(2)O_(3)/Al_(2)O_(3) CMCs.The extensive misfits in atomic weight,ionic radius among the substitutional cations in combination with the intrinsic oxygen vacancies in the anion sublattice play significant roles in the thermal conductivity reduction of(La_(0.3)Gd_(0.3)Ca_(0.4))_(2)(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))_(2)O_(7) ceramic.The combination of outstanding mechanical and thermal properties indicates that this type of material has a good application prospect for environmental/thermal barrier coatings.展开更多
Eutectic high entropy alloys are noted for their excellent castability and comprehensive mechanical properties.The excellent mechanical properties are closely related to the activation and evolution of deformation mec...Eutectic high entropy alloys are noted for their excellent castability and comprehensive mechanical properties.The excellent mechanical properties are closely related to the activation and evolution of deformation mechanisms at the atomic scale.In this work,AlCoCrFeNi2.1 alloy is taken as the research object.The mechanical behaviors and deformation mechanisms of the FCC and B2 single crystals with different orientations and the FCC/B2 composites with K-S orientation relationship during nanoindentation processes are systematically studied by molecular dynamics simulations.The results show that the mechanical behaviors of FCC single crystals are significantly orientation-dependent,meanwhile,the indentation force of[110]single crystal is the lowest at the elastic-plastic transition point,and that for[100]single crystal is the lowest in plastic deformation stage.Compared with FCC,the stress for B2 single crystals at the elastic-plastic transition point is higher.However,more deformation systems such as stacking faults,twins and dislocation loops are activated in FCC single crystal during the plastic deformation process,resulting in higher indentation force.For composites,the flow stress increases with the increase of B2 phase thickness during the initial stage of deformation.When indenter penetrates heterogeneous interface,the significantly increased deformation system in FCC phase leads to a significant increase in indentation force.The mechanical behaviors and deformation mechanisms depend on the component single crystal.When the thickness of the component layer is less than 15 nm,the heterogeneous interfaces fail to prevent the dislocation slip and improve the indentation force.The results will enrich the plastic deformation mechanisms of multi-principal eutectic alloys and provide guidance for the design of nanocrystalline metallic materials.展开更多
This work investigates how temperature and microstructural evolution affect the formability of face-centered cubic(fcc)structured CoCrFeNiMn_(0.75)Cu_(0.25) high entropy alloy(HEA)sheets under complex stress condition...This work investigates how temperature and microstructural evolution affect the formability of face-centered cubic(fcc)structured CoCrFeNiMn_(0.75)Cu_(0.25) high entropy alloy(HEA)sheets under complex stress conditions.Erichsen cupping tests were conducted to quantitatively evaluate the deformation capacity at room temperature(298 K)and cryogenic temperatures.The findings reveal a strong temperature dependence on the formability of the HEA.A decrease in the deformation temperature from 298 to 93 K causes a significant increase in both the Erichsen index(IE)(from 9.8 to 12.4 mm)and the expansion rate(δ)of surface area(from 51.6%to 76.3%),as well as a reduction in the average deviation(η)of thickness(from 55.1%to 44.4%),signifying its ultrahigh formability and uniform deformation capability at cryogenic temperature.This enhancement is attributed to the transition in the deformation mechanism from single dislocation slip at 298 K to a cooperative of plastic deformation mechanisms at 93 K,involving dislocation slip,stacking faults(SFs),Lomer-Cottrell(L-C)locks and multi-scale nanotwins.The lower stacking fault energy of the alloy facilitates these deformation mechanisms,particularly the formation of SFs and nanotwins,which enhance ductility and strength by providing additional pathways for plastic deformation.These mechanisms collectively contribute to delaying plastic instability,thereby improving the overall formability.This work provides a comprehensive understanding of the underlying reasons for the enhanced formability of HEAs at cryogenic temperatures,offering valuable insights for their practical use in challenging environments.展开更多
The effect of oxygen on the microstructure,mechanical properties and deformation behaviours of as-cast biocompatible Ti40Zr25Nb25Ta10Ox(x=0.5,1.0 and 2.0 at.%)high entropy alloys(HEAs)was investi-gated.All three oxyge...The effect of oxygen on the microstructure,mechanical properties and deformation behaviours of as-cast biocompatible Ti40Zr25Nb25Ta10Ox(x=0.5,1.0 and 2.0 at.%)high entropy alloys(HEAs)was investi-gated.All three oxygen-doped HEAs solidified as a single body-centred cubic(BCC)phase grain structure with predominantly high-angle grain boundaries following the Mackenzie prediction.Increasing oxygen content significantly increased tensile strength at a rate of about 180 MPa/1.0 at.%,but decreased ten-sile ductility.However,at the addition level of 0.5 at.%O,the as-cast Ti40Zr25Nb25Ta10O0.5 HEA can achieve a yield strength(σ_(0.2))of 947±44 MPa and an elongation at break(ε_(f))of 9.5%±1.8%.These properties make this HEA comparable to medical grade Ti-6Al-4V(wt.%)alloy(ASTM Grade 23 titanium)(σ_(0.2)≥759 MPa;ε_(f)≥10%)in itsability to absorbenergy in plasticdeformation,whileoffering greater resistance to permanent shape changes.Due to the possible strong interaction between oxygen atoms and dislocations through pinning and de-pinning,all oxygen-doped HEAs exhibited discontinuous yield-ing,whereas the low oxygen base HEA underwent normal yielding.No oxygen clusters were detected through atom probe tomography(APT)analysis.The deformation mechanism depends on oxygen con-tent.The plastic deformation of the Ti40Zr25Nb25Ta10O0.5 HEA occurred through the formation of pri-mary and secondary shear bands.In contrast,planar slip bands and a limited number of primary shear bands(without secondary shear bands)were observed in the Ti40Zr25Nb25Ta10O2.0 HEA.To ensure suf-ficient ductility,the oxygen content should be limited to 0.5 at.%.Furthermore,at this oxygen content,the corrosion resistance of the Ti40Zr25Nb25Ta10O0.5 HEA in Hank’s solution is comparable to that of Ti-6Al-4V.展开更多
The vacuum reactive wetting and brazing of Er_(2)Si_(2)O_(7)/MoSi_(2) coatings were investigated using a (CoFeNiCrMn)_(88)Nb_(12) high-entropy alloy (HEA) brazing filler. The microstructural evolution and wettability ...The vacuum reactive wetting and brazing of Er_(2)Si_(2)O_(7)/MoSi_(2) coatings were investigated using a (CoFeNiCrMn)_(88)Nb_(12) high-entropy alloy (HEA) brazing filler. The microstructural evolution and wettability of the HEA filler were analyzed, with particular attention to the surface energy, interfacial stability, and electronic properties of the HEA filler/rare earth silicate coating system, as determined by density functional theory (DFT). As Nb diffused into the interface and the ErNbO_(4) phase formed, the wetting angle gradually decreased to 23.12° The effective wetting and spreading of the HEA brazing filler on the rare earth silicate coating surface are strongly correlated with the formation of the ErNbO_(4) phase at the interface. Furthermore, DFT calculations reveal that the interfacial bonding energy between the BCC' and FCC' phases and the ErNbO_(4) phase, after the wetting reaction, is significantly higher than the bonding energy between the initial filler and Er_(2)Si_(2)O_(7). This finding suggests that the formation of the ErNbO_(4) phase improves the wetting and spreading behavior of the filler.展开更多
High-entropy materials(HEMs)show exceptional mechanical properties,highly adjustable chemical characteristics,and outstanding stability,making them suitable for energy storage.However,the broad compositional space and...High-entropy materials(HEMs)show exceptional mechanical properties,highly adjustable chemical characteristics,and outstanding stability,making them suitable for energy storage.However,the broad compositional space and intricate chemical interactions in HEMs present challenges to traditional trial-and-error research methods,restricting their efficacy in swift screening and synthesis.Hence,the application of machine learning(ML)to the realm of high-entropy materials and energy storage becomes imperative.ML demonstrates its formidable capabilities for navigating the complexity of HEMs,with their diverse metal components,structures and property combinations,to advance energy storage applications.This review comprises the following sections:a concise introduction to the general process of ML in the energy materials field,a summary of HEMs in the energy storage field,a review of the latest achievements of ML in the HEMs and energy storage field,and finally,an exploration of current challenges and prospects in this interdisciplinary arena.With the advent of ML,the precision of its predictions and the efficiency of its screening methods have offered novel perspectives for material research,expediting the discovery and application of new materials.This article contributes to the advancement of research in related fields,hastening the development of novel materials to meet the escalating energy demands and promote sustainable development goals.展开更多
The role of entropy and enthalpy plays an essential key for the formation of an alloy. This paper illustrates how an alloy is to form and what and why the properties of the alloy are going to have by the entropy and e...The role of entropy and enthalpy plays an essential key for the formation of an alloy. This paper illustrates how an alloy is to form and what and why the properties of the alloy are going to have by the entropy and enthalpy effects via a designed enthalpy-entropy plane (EE-plane) based on the Gibbs free energy equation and the introducing a charactering pseudo-unitary lattice (PUL) for entropy alloys. Based on the PUL scheme, the so-called four effects in high entropy alloys are simply nothing but the entropy effect with the other three accompanying effects: the distortion, slow diffusion and cocktail effects.展开更多
Refractory high entropy alloys(RHEAs)have drawn much attention for their potential applications in ad-vanced reactors.While improved irradiation resistance to void swelling and helium bubble formation has been frequen...Refractory high entropy alloys(RHEAs)have drawn much attention for their potential applications in ad-vanced reactors.While improved irradiation resistance to void swelling and helium bubble formation has been frequently reported,experimental investigation regarding their early-stage irradiation damage re-mains insufficient,which hinders the understanding of the behavior of point defects and small clusters.Here we select two typical RHEAs with desired mechanical properties,VTaTi and HfNbZrTi,as well as a conventional V-4Cr-4Ti alloy,and compare their irradiation-induced defect production and hardening under a low-dose irradiation to~0.1 dpa.Significant hardening is observed in V-4Cr-4Ti due to the pin-ning of deformation-induced dislocations by the high density of irradiation-induced loops.In contrast,the hardening in VTaTi is much weaker,corresponding well to the greatly reduced defect density.Strikingly,in HfNbZrTi,visible defect clusters are not observed with a Cs-corrected transmission electron microscope in the whole irradiation range,and no hardening effect is detected.Such strong suppression of irradia-tion damage is attributed to the large lattice distortion based on the ab initio calculations and the local chemical fluctuations based on the atomic-scale elemental mappings,which together hinder the mobility of interstitials.Furthermore,minor irradiation softening is evidenced by cross-sectional nanoindentation tests in HfNbZrTi,which is considered to be related to the evolution of short-range orders and interstitial impurities after irradiation.展开更多
Phase classification has a clear guiding significance for the design of high entropy alloys.For mutually exclusive and non-mutually exclusive classifications,the composition descriptors,commonly used physical paramete...Phase classification has a clear guiding significance for the design of high entropy alloys.For mutually exclusive and non-mutually exclusive classifications,the composition descriptors,commonly used physical parameter descriptors,elemental-property descriptors,and descriptors extracted from the periodic table representation(PTR)by the convolutional neural network were collected.Appropriate selection among features with rich information is helpful for phase classification.Based on random forest,the accuracy of the four-label classification and balanced accuracy of the five-label classification were improved to be 0.907 and 0.876,respectively.The roles of the four important features were summarized by interpretability analysis,and a new important feature was found.The model extrapolation ability and the influence of Mo were demonstrated by phase prediction in(CoFeNiMn)_(1-x)Mo_(x).The phase information is helpful for the hardness prediction,the classification results were coupled with the PTR of hardness data,and the prediction error(the root mean square error)was reduced to 56.69.展开更多
The phase metastability and precipitation are now considered to be an important strategy in designing Fe-rich high entropy alloys(HEAs).In this study,the influence of silicon addition on the initial and straininduced ...The phase metastability and precipitation are now considered to be an important strategy in designing Fe-rich high entropy alloys(HEAs).In this study,the influence of silicon addition on the initial and straininduced microstructure evolution and related mechanical property of Fe52−xMn27Cr15Co6Six(x=0,0.3,0.5,1.0,1.5,at.%)HEAs was systematically investigated by utilizing the in-depth microstructural characterization coupled with X-ray diffractometer(XRD),secondary electron microscopy(SEM),and transmission electron microscopy(TEM).The addition of Si to Fe52−xMn27Cr15Co6Six HEAs facilitates the triplex structure consisting of fcc-γmatrix,thermally-inducedε-martensite and sigma phase(σ).The lattice distortion energy by Si atoms is suggested to promote the formation ofσphase consisting of Cr,Si and Co and consequently influence the metastability of the matrix.In 0.3 at.%Si HEA,the strain-induced bodycentered tetragonal(bct)-typeα’-martensite were observed at the intersection of bi-directional straininducedε-martensite laths,enhancing the ultimate tensile strength to∼851 MPa from∼618.3 MPa with ductility increment(∼73.1%from∼71%).In 0.3 at.%Si and 0.5 at.%Si alloys,the granular-typeσphase was observed both at grain boundaries and in grain interior,and the size of granular-typeσphase at grain boundary and intra-granularσphase were found to be similar.The deformation mode altered from the transformation-induced plasticity(TRIP)to twinning-induced plasticity(TWIP)with an increase of Si content to 1.5 at.%,due to the enhanced fcc-γstability induced by the compositional modulation driven by increasedσphase formation.The propagation of microcracks inside brittleσphase could be suppressed by homogeneous slip through strain-induced martensite transformation(SIMT)in HEAs with low Si addition of 0.3at.%-0.5 at.%.展开更多
Zinc-nitrate battery could produce electrical power,remove pollutant nitrate and obtain value-added ammonia,where the cathodic reaction of converting nitrate to ammonia is sluggish and complex due to the involvement o...Zinc-nitrate battery could produce electrical power,remove pollutant nitrate and obtain value-added ammonia,where the cathodic reaction of converting nitrate to ammonia is sluggish and complex due to the involvement of multi-electron transfer.Thus,highly efficient catalysts for nitrate reduction reaction(NO_(3)RR)are greatly needed.In this work,we report a high entropy hydroxide(HE-OH)as an excellent NO3RR catalyst,which could achieve high NH_(3)Faradaic efficiencies(e.g.,nearly 100%at-0.3 V versus reversible hydrogen electrode)and high yield rates(e.g.,30.4 mg h^(-1)cm^(-2)at-0.4 V).Moreover,HE-OH could also deliver a current density of 10 mA/cm^(2) at an overpotential of 260 mV for oxygen evolution reaction.The assembled zinc-nitrate battery using HE-OH as the cathode demonstrates a high power density(e.g.,3.62 mW/cm^(2)),rechargeability and stability.展开更多
The performance of the fuel electrode in a solid oxide electrolysis cell(SOEC)is crucial to facilitating fuel gas electrolysis and is the key determinant of overall electrolysis efficiency.Nevertheless,the commerciali...The performance of the fuel electrode in a solid oxide electrolysis cell(SOEC)is crucial to facilitating fuel gas electrolysis and is the key determinant of overall electrolysis efficiency.Nevertheless,the commercialization of integrated CO_(2)-H_(2)O electrolysis in SOEC remains constrained by suboptimal catalytic efficiency and long-term stability limitations inherent to conventional fuel electrode architec-tures.A novel high-entropy Sr_(2)FeTi_(0.2)Cr_(0.2)Mn_(0.2)Mo_(0.2)Co_(0.2)O_(6−δ)(SFTCMMC)was proposed as a prospective electrode material of co-elec-trolysis in this work.The physicochemical properties and electrochemical performance in the co-electrolysis reaction were investigated.Full cell is capable of electrolyzing H_(2)O and CO_(2)effectively with an applied voltage.The effects of temperature,H_(2)O and CO_(2)concentra-tions,and applied voltage on the electrochemical performance of Sc_(0.18)Zr_(0.82)O_(2−δ)(SSZ)-electrolyte supported SOEC were investigated by varying the operating conditions.The SOEC obtains a favorable electrolysis current density of 1.47 A·cm^(−2)under co-electrolysis condi-tion at 850℃ with 1.5 V.Furthermore,the cell maintains stable performance for 150 h at 1.3 V,and throughout this period,no carbon de-position is detected.The promising findings suggest that the high-entropy SFTCMMC perovskite is a viable fuel electrode candidate for efficient H_(2)O/CO_(2)co-electrolysis.展开更多
The inferior structure/electrochemistry stability due to the volume expansion and the less lithium storage active sites of transition metal oxide (TMO) are critical issue hindering their commercialization.The rational...The inferior structure/electrochemistry stability due to the volume expansion and the less lithium storage active sites of transition metal oxide (TMO) are critical issue hindering their commercialization.The rational design to utilize the combined advantages of both structure and composition is a key strategy to address these challenges.Here,the (FeCoNiMnCrMg)_(2)O_(3)high entropy oxide(HEO) with different morphologic structures are developed through integrating molecule and microstructure engineering.The morphologic structure of high entropy oxide transforms from solid spheres to multishelled core-shell spheres,and then to hollow spheres,which is governed by a thermally induced non-uniform shrinkage process coupled with Kirkendall effect diffusion due to the different calcination temperature.Even with the incorporation of various metallic ions,the high entropy oxide with a homogeneous single-phase solid solution maintained their shape and uniformity in size due to the ability of metal ions to coexist on the same lattice point.Benefiting from the meticulous control of both compositional and geometric factors,the hollow high entropy oxide exhibited a significantly high specific capacity (1722.1 mAh g^(-1)after 200cycles at 1 A g^(-1)) and long-life span for lithium storage(2158.7 mAh g^(-1)over 900 cycles at 4 A g^(-1)).The collaborative lattice and consistent volume demonstrated in this study offer significant potential in directing the development of materials for advanced energy storage solutions.展开更多
High entropy materials(HEMs)show great potential as electrocatalysts for oxygen evolution reaction(OER)thanks to their interesting four-core effect.This paper presents the first systematic summary of the key factors i...High entropy materials(HEMs)show great potential as electrocatalysts for oxygen evolution reaction(OER)thanks to their interesting four-core effect.This paper presents the first systematic summary of the key factors in the synthetic methods and their influence on the structure and OER properties of HEMs(including complexing agent,synthetic temperature,and calcination atmosphere).Optimizing the components of high entropy alloys and compounds by introducing heteroatoms(such as O,S,P,N,C,and B)can enhance the chemical configurations of active sites and thus enhance the intrinsic OER kinetics.In addition,this paper emphasizes the importance of the electrocatalytic influence mechanism of the four-core effects(including the high entropy effect,lattice distortion effect,cocktail effect and sluggish diffusion effect)on catalyst structure and their OER performance.Finally,we outline the current challenges and future development directions,aiming to offer crucial insights for creating economical and efficient HEM-based electrocatalysts in the OER field.展开更多
Ensuring the long-term and stable operation of mechanical equipment has been a research emphasis with the development of aerospace and polar exploration,which necessitates the prepared materials with high mechanical s...Ensuring the long-term and stable operation of mechanical equipment has been a research emphasis with the development of aerospace and polar exploration,which necessitates the prepared materials with high mechanical strength as well as excellent wear resistance[1].The traditional lubricant is widely acknowledged to be susceptible to evaporation or decomposition under extreme conditions,necessitating the deposition of a protective thin film on critical mechanical parts’surfaces to enhance their mechanical and tribological properties[2,3].展开更多
Diffusion bonding(DB)with interlayers is sought-after for manufacturing high-performance turbine disks of powder metallurgy(PM)superalloys with precise and intricate inner cavity structures.Developing novel interlayer...Diffusion bonding(DB)with interlayers is sought-after for manufacturing high-performance turbine disks of powder metallurgy(PM)superalloys with precise and intricate inner cavity structures.Developing novel interlayer materials is challenging but crucial for enhancing bonding quality and joint properties.We designed a multi-interlayer composite bonding(MICB)method,employing sandwich-structured inter-layers of"BNi2/high entropy alloy(HEA)/BNi2",to join a PM superalloy FGH98.The MICB joint exhibited an ultrahigh shear strength of~1132 MPa and exceptional ductility,indicating a typical ductile fracture pattern with numerous dimples.Owing to the introduction of liquid BNi2 interlayer,initial bonding in-terfaces were eliminated and replaced by newborn grain boundaries(GBs),preventing brittle interfacial fracture.Due to the diffusion of Al/Ti/Ta from the base metals(BMs),massive orderedγ'nanoparticles also precipitated in the joint.Moreover,the addition of HEA foil reduced the stacking fault energy(SFE)of the joint and facilitated the formation of deformation twins(DTs).Thus,during the deformation process,theγ'nanoparticles,and multiple substructures like stacking faults(SFs),Lomer-Cottrell(L-C)locks,DTs,and 9R phases enhanced the work-hardening capability and strengthened the joint.Simultaneously,the multiplication and interaction of DTs induced a softening mechanism of dynamic recrystallization(DRX)during the entire deformation process and dominated when the plastic instability occurred,resulting in numerous adiabatic shear bands(ASBs)consisting ofγ/γ'nano-bands,which indicates a significant im-provement of the joint ductility.展开更多
基金Supported by National Natural Science Foundation of China(Grant No.52275412)Fundamental Research Funds for the Central Universities of China(Grant No.N2403015).
文摘High entropy alloy attracts widespread attention due to its excellent mechanical properties.It becomes a new type of alloy material with high application potential,but the grinding performance of High entropy alloy receives little attention.This paper conducts grinding simulation and surface grinding experiments on FeCoCrNi high entropy and alloys to analyze the grinding removal mechanism of the FeCoCrNi-based High entropy alloy.We also discuss the influence of grinding parameters,element types,element content and forming methods on grinding force and sub-surface plastic deformation after grinding.The simulation and experimental results show that as the increase of grinding depth,both tangential grinding force and normal grinding force increase,and the thickness of sub-surface plastic deformation layer decreases.With the increase of grinding speed,both tangential grinding force and normal grinding force decrease,and the thickness of sub-surface plastic deformation layer caused by grinding process shows a trend of gradual decrease.Under the same processing parameters,the normal grinding force is greater than the tangential grinding force.In FeCoCrNi series high entropy alloys,the grinding force and subsurface plastic deformation layer thickness of high entropy alloys increased with the addition in Ti content.The grinding force and plastic deformation formed by adding Ti element are greater than those formed by adding Al element,and High entropy alloys prepared using laser cladding method exhibit greater grinding force and plastic deformation than those prepared using selective laser melting method.The research results provide theoretical reference and experimental basis for high-quality grinding of high entropy alloys,which may be helpful for the design and manufacturing of high entropy alloy parts.
基金supported by National Natural Science Foundation of China(Grant No.52171032)Hebei Natural Science Foundation(Grant No.E2023501002)Fundamental Research Funds for the Central Universities(Grant No.2024GFYD003)。
文摘High entropy alloys(HEAs)have recently attracted significant attention due to their exceptional mechanical properties and potential applications across various fields.Friction stir welding and processing(FSW/P),as notable solid-state welding and processing techniques,have been proved effectiveness in enhancing microstructures and mechanical properties of HEAs.This review article summarizes the current status of FSW/P of HEAs.The welding materials and conditions used for FSW/P in HEAs are reviewed and discussed.The effects of FSW/P on the evolutions of grain structure,texture,dislocation,and secondary phase for different HEAs are highlighted.Furthermore,the influences of FSW/P on the mechanical properties of various HEAs are analyzed.Finally,potential applications,challenges,and future directions of FSW/P in HEAs are forecasted.Overall,FSW/P enable to refine grains of HEAs through dynamic recrystallization and to activate diverse deformation mechanisms of HEAs through tailoring phase structures,thereby significantly improving the strength,hardness,and ductility of both single-and dual-phase HEAs.Future progress in this field will rely on comprehensive optimization of processing parameters and alloy composition,integration of multi-scale modeling with advanced characterization for in-depth exploration of microstructural mechanisms,systematic evaluation of functional properties,and effective bridging of the gap between laboratory research and industrial application.The review aims to provide an overview of recent advancements in the FSW/P of HEAs and encourage further research in this area.
基金supported by Fundamental Research Funds for the Central Universities(2023KYJD1008)the Science Research Projects of the Anhui Higher Education Institutions of China(2022AH051582).
文摘Reversible solid oxide cell(RSOC)is a new energy conversion device with significant applications,especially for power grid peaking shaving.However,the reversible conversion process of power generation/energy storage poses challenges for the performance and stability of air electrodes.In this work,a novel high-entropy perovskite oxide La_(0.2)Pr_(0.2)Gd_(0.2)Sm_(0.2)Sr_(0.2)Co_(0.8)Fe_(0.2)O_(3−δ)(HE-LSCF)is proposed and investigated as an air electrode in RSOC.The electrochemical behavior of HE-LSCF was studied as an air electrode in both fuel cell and electrolysis modes.The polarization impedance(Rp)of the HE-LSCF electrode is only 0.25Ω·cm^(2) at 800℃ in an air atmosphere.Notably,at an electrolytic voltage of 2 V and a temperature of 800℃,the current density reaches up to 1.68 A/cm^(2).The HE-LSCF air electrode exhibited excellent reversibility and stability,and its electrochemical performance remains stable after 100 h of reversible operation.With these advantages,HE-LSCF is shown to be an excellent air electrode for RSOC.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF0609000)National Natural Science Foundation of China(Grant Nos.52171034 and 52101037)Postdoctoral Fellowship Program of CPSFara(No.GZB20230944).
文摘Up-and-coming high-temperature materials,refractory high entropy alloys,are suffering from lower oxidation resistance,restricting their applications in the aerospace field.In this study,two novel treatments of Al-deposited and remelted were developed to refine the microstructure and enhance the oxidation resistance of refractory high entropy alloy using electron beam freeform fabrication(EBF3).Finer and short-range ordering structures were observed in the remelted sample,whereas the Al-deposited sample showcased the formation of silicide and intermetallic phases.High-temperature cyclic and isothermal oxidation tests at 1000℃ were carried out.The total weight gain after 60 h of cyclic oxidation decreased by 17.49%and 30.46%for the remelted and deposited samples,respectively,compared to the as-cast state.Oxidation kinetics reveal an evident lower mass gain and oxidation rate in the treated samples.A multilayer oxide consisting of TiO_(2)+Al_(2)O_(3)+SiO_(2)+AlNbO_(4) was studied for its excellent oxidation resistance.The oxidation behavior of rutile,corundum and other oxides was analyzed using first principles calculations and chemical defect analysis.Overall,this research,which introduces novel treatments,offers promising insights for enhancing the inherent oxidation resistance of refractory high entropy alloys.
基金support from the National Natural Science Foundation of China under grant No.52302065the Yunnan Fundamental Research Projects under grant Nos.202201BE070001-008 and 202201AU070142the National Key Research and Development Program of China under grant No.2023YFB3711200.
文摘Low thermal conductivity and excellent mechanical strength are essential to pyrochlore A2B2O7 ceramic for environmental/thermal barrier coating applications.To collaboratively tailor the mechanical and thermal properties of A2B2O7 ceramic,a novel high entropy pyrochlore ceramic(La_(0.3)Gd_(0.3)Ca_(0.4))_(2)(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))_(2)O_(7) with significant atomic radius and mass fluctuation is proposed by simultaneously introducing various elements with different valence states at A and B cation sites.The as-synthesized(La_(0.3)Gd_(0.3)Ca_(0.4))_(2)(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))_(2)O_(7) exhibits enhanced fracture toughness(1.68 MPa m^(1/2)),amorphous-like low thermal conductivity(1.45 W m^(-1) K^(-1) at 900℃)and matched thermal expansion coefficient(9.0×10^(-6) K^(-1) at 1200℃)with Al_(2)O_(3)/Al_(2)O_(3) CMCs.The extensive misfits in atomic weight,ionic radius among the substitutional cations in combination with the intrinsic oxygen vacancies in the anion sublattice play significant roles in the thermal conductivity reduction of(La_(0.3)Gd_(0.3)Ca_(0.4))_(2)(Ti_(0.2)Zr_(0.2)Hf_(0.2)Nb_(0.2)Ta_(0.2))_(2)O_(7) ceramic.The combination of outstanding mechanical and thermal properties indicates that this type of material has a good application prospect for environmental/thermal barrier coatings.
基金supported by the Natural Science Foundation of Hebei Province(E2024209052)the Youth Scholars Promotion Plan of North China University of Science and Technology(QNTJ202307).
文摘Eutectic high entropy alloys are noted for their excellent castability and comprehensive mechanical properties.The excellent mechanical properties are closely related to the activation and evolution of deformation mechanisms at the atomic scale.In this work,AlCoCrFeNi2.1 alloy is taken as the research object.The mechanical behaviors and deformation mechanisms of the FCC and B2 single crystals with different orientations and the FCC/B2 composites with K-S orientation relationship during nanoindentation processes are systematically studied by molecular dynamics simulations.The results show that the mechanical behaviors of FCC single crystals are significantly orientation-dependent,meanwhile,the indentation force of[110]single crystal is the lowest at the elastic-plastic transition point,and that for[100]single crystal is the lowest in plastic deformation stage.Compared with FCC,the stress for B2 single crystals at the elastic-plastic transition point is higher.However,more deformation systems such as stacking faults,twins and dislocation loops are activated in FCC single crystal during the plastic deformation process,resulting in higher indentation force.For composites,the flow stress increases with the increase of B2 phase thickness during the initial stage of deformation.When indenter penetrates heterogeneous interface,the significantly increased deformation system in FCC phase leads to a significant increase in indentation force.The mechanical behaviors and deformation mechanisms depend on the component single crystal.When the thickness of the component layer is less than 15 nm,the heterogeneous interfaces fail to prevent the dislocation slip and improve the indentation force.The results will enrich the plastic deformation mechanisms of multi-principal eutectic alloys and provide guidance for the design of nanocrystalline metallic materials.
基金supported by the National Natural Science Foundation of China(Nos.52371025 and 52371106)Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030001)Shenzhen Fund 2021 Basic Research General Programme(No.JCYJ20210324115400002).
文摘This work investigates how temperature and microstructural evolution affect the formability of face-centered cubic(fcc)structured CoCrFeNiMn_(0.75)Cu_(0.25) high entropy alloy(HEA)sheets under complex stress conditions.Erichsen cupping tests were conducted to quantitatively evaluate the deformation capacity at room temperature(298 K)and cryogenic temperatures.The findings reveal a strong temperature dependence on the formability of the HEA.A decrease in the deformation temperature from 298 to 93 K causes a significant increase in both the Erichsen index(IE)(from 9.8 to 12.4 mm)and the expansion rate(δ)of surface area(from 51.6%to 76.3%),as well as a reduction in the average deviation(η)of thickness(from 55.1%to 44.4%),signifying its ultrahigh formability and uniform deformation capability at cryogenic temperature.This enhancement is attributed to the transition in the deformation mechanism from single dislocation slip at 298 K to a cooperative of plastic deformation mechanisms at 93 K,involving dislocation slip,stacking faults(SFs),Lomer-Cottrell(L-C)locks and multi-scale nanotwins.The lower stacking fault energy of the alloy facilitates these deformation mechanisms,particularly the formation of SFs and nanotwins,which enhance ductility and strength by providing additional pathways for plastic deformation.These mechanisms collectively contribute to delaying plastic instability,thereby improving the overall formability.This work provides a comprehensive understanding of the underlying reasons for the enhanced formability of HEAs at cryogenic temperatures,offering valuable insights for their practical use in challenging environments.
文摘The effect of oxygen on the microstructure,mechanical properties and deformation behaviours of as-cast biocompatible Ti40Zr25Nb25Ta10Ox(x=0.5,1.0 and 2.0 at.%)high entropy alloys(HEAs)was investi-gated.All three oxygen-doped HEAs solidified as a single body-centred cubic(BCC)phase grain structure with predominantly high-angle grain boundaries following the Mackenzie prediction.Increasing oxygen content significantly increased tensile strength at a rate of about 180 MPa/1.0 at.%,but decreased ten-sile ductility.However,at the addition level of 0.5 at.%O,the as-cast Ti40Zr25Nb25Ta10O0.5 HEA can achieve a yield strength(σ_(0.2))of 947±44 MPa and an elongation at break(ε_(f))of 9.5%±1.8%.These properties make this HEA comparable to medical grade Ti-6Al-4V(wt.%)alloy(ASTM Grade 23 titanium)(σ_(0.2)≥759 MPa;ε_(f)≥10%)in itsability to absorbenergy in plasticdeformation,whileoffering greater resistance to permanent shape changes.Due to the possible strong interaction between oxygen atoms and dislocations through pinning and de-pinning,all oxygen-doped HEAs exhibited discontinuous yield-ing,whereas the low oxygen base HEA underwent normal yielding.No oxygen clusters were detected through atom probe tomography(APT)analysis.The deformation mechanism depends on oxygen con-tent.The plastic deformation of the Ti40Zr25Nb25Ta10O0.5 HEA occurred through the formation of pri-mary and secondary shear bands.In contrast,planar slip bands and a limited number of primary shear bands(without secondary shear bands)were observed in the Ti40Zr25Nb25Ta10O2.0 HEA.To ensure suf-ficient ductility,the oxygen content should be limited to 0.5 at.%.Furthermore,at this oxygen content,the corrosion resistance of the Ti40Zr25Nb25Ta10O0.5 HEA in Hank’s solution is comparable to that of Ti-6Al-4V.
基金support from the National Natural Science Foundation of China(No.52374402)the National Key Research and Development Program(No.2022YFB3402200)+2 种基金the National Science and Technology Major Project(No.J2022-VII-0003-0045)the Project of Key areas of innovation team in Shaanxi Province(No.2024RS-CXTD-20)the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University(No.CX2024055).
文摘The vacuum reactive wetting and brazing of Er_(2)Si_(2)O_(7)/MoSi_(2) coatings were investigated using a (CoFeNiCrMn)_(88)Nb_(12) high-entropy alloy (HEA) brazing filler. The microstructural evolution and wettability of the HEA filler were analyzed, with particular attention to the surface energy, interfacial stability, and electronic properties of the HEA filler/rare earth silicate coating system, as determined by density functional theory (DFT). As Nb diffused into the interface and the ErNbO_(4) phase formed, the wetting angle gradually decreased to 23.12° The effective wetting and spreading of the HEA brazing filler on the rare earth silicate coating surface are strongly correlated with the formation of the ErNbO_(4) phase at the interface. Furthermore, DFT calculations reveal that the interfacial bonding energy between the BCC' and FCC' phases and the ErNbO_(4) phase, after the wetting reaction, is significantly higher than the bonding energy between the initial filler and Er_(2)Si_(2)O_(7). This finding suggests that the formation of the ErNbO_(4) phase improves the wetting and spreading behavior of the filler.
基金supported by the National Natural Science Foundation of China(22005072,21965006)Guiyang Guian science and Technology Personnel Training Project(2024-2-13)+1 种基金Guizhou Provincial Key Technology R&D Program(Qian Ke He support(2023)General 122)Guizhou Provincial Science and Technology Foundation(ZD2025049,KXJZ2024029).
文摘High-entropy materials(HEMs)show exceptional mechanical properties,highly adjustable chemical characteristics,and outstanding stability,making them suitable for energy storage.However,the broad compositional space and intricate chemical interactions in HEMs present challenges to traditional trial-and-error research methods,restricting their efficacy in swift screening and synthesis.Hence,the application of machine learning(ML)to the realm of high-entropy materials and energy storage becomes imperative.ML demonstrates its formidable capabilities for navigating the complexity of HEMs,with their diverse metal components,structures and property combinations,to advance energy storage applications.This review comprises the following sections:a concise introduction to the general process of ML in the energy materials field,a summary of HEMs in the energy storage field,a review of the latest achievements of ML in the HEMs and energy storage field,and finally,an exploration of current challenges and prospects in this interdisciplinary arena.With the advent of ML,the precision of its predictions and the efficiency of its screening methods have offered novel perspectives for material research,expediting the discovery and application of new materials.This article contributes to the advancement of research in related fields,hastening the development of novel materials to meet the escalating energy demands and promote sustainable development goals.
文摘The role of entropy and enthalpy plays an essential key for the formation of an alloy. This paper illustrates how an alloy is to form and what and why the properties of the alloy are going to have by the entropy and enthalpy effects via a designed enthalpy-entropy plane (EE-plane) based on the Gibbs free energy equation and the introducing a charactering pseudo-unitary lattice (PUL) for entropy alloys. Based on the PUL scheme, the so-called four effects in high entropy alloys are simply nothing but the entropy effect with the other three accompanying effects: the distortion, slow diffusion and cocktail effects.
基金supported by the National MCF En-ergy R&D Program of China(No.2022YFE03120000)the Na-tional Natural Science Foundation of China(Nos.12375266 and 12435016).
文摘Refractory high entropy alloys(RHEAs)have drawn much attention for their potential applications in ad-vanced reactors.While improved irradiation resistance to void swelling and helium bubble formation has been frequently reported,experimental investigation regarding their early-stage irradiation damage re-mains insufficient,which hinders the understanding of the behavior of point defects and small clusters.Here we select two typical RHEAs with desired mechanical properties,VTaTi and HfNbZrTi,as well as a conventional V-4Cr-4Ti alloy,and compare their irradiation-induced defect production and hardening under a low-dose irradiation to~0.1 dpa.Significant hardening is observed in V-4Cr-4Ti due to the pin-ning of deformation-induced dislocations by the high density of irradiation-induced loops.In contrast,the hardening in VTaTi is much weaker,corresponding well to the greatly reduced defect density.Strikingly,in HfNbZrTi,visible defect clusters are not observed with a Cs-corrected transmission electron microscope in the whole irradiation range,and no hardening effect is detected.Such strong suppression of irradia-tion damage is attributed to the large lattice distortion based on the ab initio calculations and the local chemical fluctuations based on the atomic-scale elemental mappings,which together hinder the mobility of interstitials.Furthermore,minor irradiation softening is evidenced by cross-sectional nanoindentation tests in HfNbZrTi,which is considered to be related to the evolution of short-range orders and interstitial impurities after irradiation.
基金supported by the National Natural Science Foundation of China(Nos.51671075,51971086)the Natural Science Foundation of Heilongjiang Province,China(No.LH2022E081)。
文摘Phase classification has a clear guiding significance for the design of high entropy alloys.For mutually exclusive and non-mutually exclusive classifications,the composition descriptors,commonly used physical parameter descriptors,elemental-property descriptors,and descriptors extracted from the periodic table representation(PTR)by the convolutional neural network were collected.Appropriate selection among features with rich information is helpful for phase classification.Based on random forest,the accuracy of the four-label classification and balanced accuracy of the five-label classification were improved to be 0.907 and 0.876,respectively.The roles of the four important features were summarized by interpretability analysis,and a new important feature was found.The model extrapolation ability and the influence of Mo were demonstrated by phase prediction in(CoFeNiMn)_(1-x)Mo_(x).The phase information is helpful for the hardness prediction,the classification results were coupled with the PTR of hardness data,and the prediction error(the root mean square error)was reduced to 56.69.
基金financially supported by the National Research Foundation of Korea(NRF)grants funded by the Korean Govern-ment(Nos.RS-2023-00281246 and RS-2024-00398068)the grant(No.360-05-01-PNK9690)by the Department of Hydrogen Materials Evaluation at Korea Institute of Materials Science(KIMS).
文摘The phase metastability and precipitation are now considered to be an important strategy in designing Fe-rich high entropy alloys(HEAs).In this study,the influence of silicon addition on the initial and straininduced microstructure evolution and related mechanical property of Fe52−xMn27Cr15Co6Six(x=0,0.3,0.5,1.0,1.5,at.%)HEAs was systematically investigated by utilizing the in-depth microstructural characterization coupled with X-ray diffractometer(XRD),secondary electron microscopy(SEM),and transmission electron microscopy(TEM).The addition of Si to Fe52−xMn27Cr15Co6Six HEAs facilitates the triplex structure consisting of fcc-γmatrix,thermally-inducedε-martensite and sigma phase(σ).The lattice distortion energy by Si atoms is suggested to promote the formation ofσphase consisting of Cr,Si and Co and consequently influence the metastability of the matrix.In 0.3 at.%Si HEA,the strain-induced bodycentered tetragonal(bct)-typeα’-martensite were observed at the intersection of bi-directional straininducedε-martensite laths,enhancing the ultimate tensile strength to∼851 MPa from∼618.3 MPa with ductility increment(∼73.1%from∼71%).In 0.3 at.%Si and 0.5 at.%Si alloys,the granular-typeσphase was observed both at grain boundaries and in grain interior,and the size of granular-typeσphase at grain boundary and intra-granularσphase were found to be similar.The deformation mode altered from the transformation-induced plasticity(TRIP)to twinning-induced plasticity(TWIP)with an increase of Si content to 1.5 at.%,due to the enhanced fcc-γstability induced by the compositional modulation driven by increasedσphase formation.The propagation of microcracks inside brittleσphase could be suppressed by homogeneous slip through strain-induced martensite transformation(SIMT)in HEAs with low Si addition of 0.3at.%-0.5 at.%.
基金financially supported by the National Natural Science Foundation of China(Nos.22209040 and 22202063)。
文摘Zinc-nitrate battery could produce electrical power,remove pollutant nitrate and obtain value-added ammonia,where the cathodic reaction of converting nitrate to ammonia is sluggish and complex due to the involvement of multi-electron transfer.Thus,highly efficient catalysts for nitrate reduction reaction(NO_(3)RR)are greatly needed.In this work,we report a high entropy hydroxide(HE-OH)as an excellent NO3RR catalyst,which could achieve high NH_(3)Faradaic efficiencies(e.g.,nearly 100%at-0.3 V versus reversible hydrogen electrode)and high yield rates(e.g.,30.4 mg h^(-1)cm^(-2)at-0.4 V).Moreover,HE-OH could also deliver a current density of 10 mA/cm^(2) at an overpotential of 260 mV for oxygen evolution reaction.The assembled zinc-nitrate battery using HE-OH as the cathode demonstrates a high power density(e.g.,3.62 mW/cm^(2)),rechargeability and stability.
基金supported by the National Natural Science Foundation of China(No.52472270)the Basic Research Program of Jiangsu(No.BK20243049)the Fundamental Research Funds for the Central Universities(No.2023KYJD1010).
文摘The performance of the fuel electrode in a solid oxide electrolysis cell(SOEC)is crucial to facilitating fuel gas electrolysis and is the key determinant of overall electrolysis efficiency.Nevertheless,the commercialization of integrated CO_(2)-H_(2)O electrolysis in SOEC remains constrained by suboptimal catalytic efficiency and long-term stability limitations inherent to conventional fuel electrode architec-tures.A novel high-entropy Sr_(2)FeTi_(0.2)Cr_(0.2)Mn_(0.2)Mo_(0.2)Co_(0.2)O_(6−δ)(SFTCMMC)was proposed as a prospective electrode material of co-elec-trolysis in this work.The physicochemical properties and electrochemical performance in the co-electrolysis reaction were investigated.Full cell is capable of electrolyzing H_(2)O and CO_(2)effectively with an applied voltage.The effects of temperature,H_(2)O and CO_(2)concentra-tions,and applied voltage on the electrochemical performance of Sc_(0.18)Zr_(0.82)O_(2−δ)(SSZ)-electrolyte supported SOEC were investigated by varying the operating conditions.The SOEC obtains a favorable electrolysis current density of 1.47 A·cm^(−2)under co-electrolysis condi-tion at 850℃ with 1.5 V.Furthermore,the cell maintains stable performance for 150 h at 1.3 V,and throughout this period,no carbon de-position is detected.The promising findings suggest that the high-entropy SFTCMMC perovskite is a viable fuel electrode candidate for efficient H_(2)O/CO_(2)co-electrolysis.
基金financially supported by the Central Guidance on Local Science and Technology Development Fund of Sichuan Province(No.2023ZYDF044)LingYan Project(No.2024C01090)
文摘The inferior structure/electrochemistry stability due to the volume expansion and the less lithium storage active sites of transition metal oxide (TMO) are critical issue hindering their commercialization.The rational design to utilize the combined advantages of both structure and composition is a key strategy to address these challenges.Here,the (FeCoNiMnCrMg)_(2)O_(3)high entropy oxide(HEO) with different morphologic structures are developed through integrating molecule and microstructure engineering.The morphologic structure of high entropy oxide transforms from solid spheres to multishelled core-shell spheres,and then to hollow spheres,which is governed by a thermally induced non-uniform shrinkage process coupled with Kirkendall effect diffusion due to the different calcination temperature.Even with the incorporation of various metallic ions,the high entropy oxide with a homogeneous single-phase solid solution maintained their shape and uniformity in size due to the ability of metal ions to coexist on the same lattice point.Benefiting from the meticulous control of both compositional and geometric factors,the hollow high entropy oxide exhibited a significantly high specific capacity (1722.1 mAh g^(-1)after 200cycles at 1 A g^(-1)) and long-life span for lithium storage(2158.7 mAh g^(-1)over 900 cycles at 4 A g^(-1)).The collaborative lattice and consistent volume demonstrated in this study offer significant potential in directing the development of materials for advanced energy storage solutions.
基金supported by the National Natural Science Foundation of China(52103342 and 22209032)the Scientific Research Fund of Zhejiang Provincial Education Department(Y202456353)。
文摘High entropy materials(HEMs)show great potential as electrocatalysts for oxygen evolution reaction(OER)thanks to their interesting four-core effect.This paper presents the first systematic summary of the key factors in the synthetic methods and their influence on the structure and OER properties of HEMs(including complexing agent,synthetic temperature,and calcination atmosphere).Optimizing the components of high entropy alloys and compounds by introducing heteroatoms(such as O,S,P,N,C,and B)can enhance the chemical configurations of active sites and thus enhance the intrinsic OER kinetics.In addition,this paper emphasizes the importance of the electrocatalytic influence mechanism of the four-core effects(including the high entropy effect,lattice distortion effect,cocktail effect and sluggish diffusion effect)on catalyst structure and their OER performance.Finally,we outline the current challenges and future development directions,aiming to offer crucial insights for creating economical and efficient HEM-based electrocatalysts in the OER field.
基金the National Natural Science Foundation of China(No.52175188)the Key Research and De-velopment Program of Shaanxi Province(No.2023-YBGY-434)+2 种基金the Open Fund of Liaoning Provincial Key Laboratory of Aero-engine Materials Tribology(No.LKLAMTF202301)the Guangdong Basic and Applied Basic Research Foundation(No.2024A1515012378)the Science and Technology on Reactor System Design Tech-nology Laboratory and the Fundamental Research Funds for the Central Universities.
文摘Ensuring the long-term and stable operation of mechanical equipment has been a research emphasis with the development of aerospace and polar exploration,which necessitates the prepared materials with high mechanical strength as well as excellent wear resistance[1].The traditional lubricant is widely acknowledged to be susceptible to evaporation or decomposition under extreme conditions,necessitating the deposition of a protective thin film on critical mechanical parts’surfaces to enhance their mechanical and tribological properties[2,3].
基金support from the National Natural Science Foundation of China(Grant Nos.52075449,51975480,and 52222112)the Hong Kong Research Grant Council(RGC)(Grant No.21205621).
文摘Diffusion bonding(DB)with interlayers is sought-after for manufacturing high-performance turbine disks of powder metallurgy(PM)superalloys with precise and intricate inner cavity structures.Developing novel interlayer materials is challenging but crucial for enhancing bonding quality and joint properties.We designed a multi-interlayer composite bonding(MICB)method,employing sandwich-structured inter-layers of"BNi2/high entropy alloy(HEA)/BNi2",to join a PM superalloy FGH98.The MICB joint exhibited an ultrahigh shear strength of~1132 MPa and exceptional ductility,indicating a typical ductile fracture pattern with numerous dimples.Owing to the introduction of liquid BNi2 interlayer,initial bonding in-terfaces were eliminated and replaced by newborn grain boundaries(GBs),preventing brittle interfacial fracture.Due to the diffusion of Al/Ti/Ta from the base metals(BMs),massive orderedγ'nanoparticles also precipitated in the joint.Moreover,the addition of HEA foil reduced the stacking fault energy(SFE)of the joint and facilitated the formation of deformation twins(DTs).Thus,during the deformation process,theγ'nanoparticles,and multiple substructures like stacking faults(SFs),Lomer-Cottrell(L-C)locks,DTs,and 9R phases enhanced the work-hardening capability and strengthened the joint.Simultaneously,the multiplication and interaction of DTs induced a softening mechanism of dynamic recrystallization(DRX)during the entire deformation process and dominated when the plastic instability occurred,resulting in numerous adiabatic shear bands(ASBs)consisting ofγ/γ'nano-bands,which indicates a significant im-provement of the joint ductility.
