Short-range ordering(SRO)is one of the most important structural features of high entropy alloys(HEAs).However,the chemical and structural analyses of SROs are very difficult due to their small size,complexed composit...Short-range ordering(SRO)is one of the most important structural features of high entropy alloys(HEAs).However,the chemical and structural analyses of SROs are very difficult due to their small size,complexed compositions,and varied locations.Transmission electron microscopy(TEM)as well as its aberration correction techniques are powerful for characterizing SROs in these compositionally complex alloys.In this short communication,we summarized recent progresses regarding characterization of SROs using TEM in the field of HEAs.By using advanced TEM techniques,not only the existence of SROs was confirmed,but also the effect of SROs on the deformation mechanism was clarified.Moreover,the perspective related to application of TEM techniques in HEAs are also discussed.展开更多
The coupling effects of the metastable austenitic phase and the amorphous matrix in a transformation-induced plasticity(TRIP)-reinforced bulk metallic glass(BMG)composite under compressive loading were investigated by...The coupling effects of the metastable austenitic phase and the amorphous matrix in a transformation-induced plasticity(TRIP)-reinforced bulk metallic glass(BMG)composite under compressive loading were investigated by employing the digital image correlation(DIC)technique.The evolution of local strain field in the crystalline phase and the amorphous matrix was directly monitored,and the contribution from the phase transformation of the metastable austenitic phase was revealed.Local shear strain was found to be effectively consumed by the displacive phase transformation of the metastable austenitic phase,which relaxed the local strain/stress concentration at the interface and thus greatly enhanced the plasticity of the TRIP-reinforced BMG composites.Our current study sheds light on in-depth understanding of the underlying deformation mechanism and the interplay between the amorphous matrix and the metastable crystalline phase during deformation,which is helpful for design of advanced BMG composites with further improved properties.展开更多
1.Introduction High entropy alloys(HEAs),arising from the incorporation of multiple principal elements[1,2],have garnered extensive atten-tion due to their great potential to be utilized under extreme con-ditions[3-5].
Producing ultrafine-grained(UFG)microstructures with enhanced thermal stability is an important yet challenging route to further improve mechanical properties of structural materials.Here,a high-performance bulk UFG c...Producing ultrafine-grained(UFG)microstructures with enhanced thermal stability is an important yet challenging route to further improve mechanical properties of structural materials.Here,a high-performance bulk UFG copper that can stabilize even at temperatures up to 750℃(∼0.75 T m,T m is the melting point)was fabricated by manipulating its recrystallization behavior via low alloying of Co.Addition of 1 wt.%–1.5 wt.%of Co can trigger quick and copious intragranular clustering of Co atoms,which offers high Zener pinning pressure and pins the grain boundaries(GBs)of freshly recrystallized ul-trafine grains.Due to the fact that the subsequent growth of the coherent Co-enriched nanoclusters was slow,sufficient particles adjacent to GBs remained to inhibit the migration of GBs,giving rise to the UFG microstructure with prominently high thermal stability.This work manifests that the strategy for pro-ducing UFGs with coherent precipitates can be applied in many alloy systems such as Fe-and Cu-based,which paves the pathway for designing advanced strain-hardenable UFGs with plain compositions.展开更多
Alloys with a hexagonal close-packed(HCP)lattice often suffer from intrinsic brittleness due to their in-sufficient number of slip systems,which limits their practical uses.In this paper,nevertheless,we show that rema...Alloys with a hexagonal close-packed(HCP)lattice often suffer from intrinsic brittleness due to their in-sufficient number of slip systems,which limits their practical uses.In this paper,nevertheless,we show that remarkably tensile ductility in HCP Hf-Zr-Ti medium entropy alloys(MEAs)was achieved,particu-larly in the MEAs with a higher content of Hf.Both first-principles calculation and experimental analyses reveal that addition of Hf increases basal I2 stacking fault energy and decreases prismatic stacking fault energy in these HCP MEAs,which promotes the source of pyramidal dislocations due to the facilitated cross slips of basal dislocations and eventually give rise to the observed large tensile ductility.Our current findings not only shed new insights into understanding deformation of HCP alloys,but also provide a basis for controlling alloying effects for developing novel HCP complex alloys with optimized properties.展开更多
Multi-principal element alloys(MPEAs)have attracted much attention as future nuclear materials due to their extraordinary radiation resistances.In this work,we have elucidated the development of local chemical orderin...Multi-principal element alloys(MPEAs)have attracted much attention as future nuclear materials due to their extraordinary radiation resistances.In this work,we have elucidated the development of local chemical orderings(LCOs)and their influences on radiation damage behavior in the typical CrFeNi MPEA by hybrid-molecular dynamics and Monte Carlo simulations.It was found that considerable LCOs consist-ing of the Cr-Cr and Ni-Fe short-range orders existed in the ordered configuration with optimized system energy.Through modeling the accumulation cascades up to 1000 recoils,we revealed that the size of de-fect clusters and dislocation loops is smaller in the ordered configuration than those in the random one,although the former formed more Frenkel pairs(i.e.,self-interstitials and vacancies).In addition,the dis-tribution of dislocation loops is relatively more dispersed in the ordered configuration,and the stair-rod dislocations related to irradiation swelling are also smaller,implying that the existence of LCOs is con-ducive to enhancing radiation damage tolerance.To understand the underlying mechanism,the effects of LCOs on the formation and evolution of defects and radiation resistance were discussed from the aspects of atomic bonding,migration path,and energy of defect diffusion,which provides theoretical guidance for the design of MPEAs with enhanced radiation resistance.展开更多
Metallic glasses(MGs)have attracted extensive attention in the past decades due to their unique chem-ical,physical and mechanical properties promising for a wide range of engineering applications.A thor-ough understan...Metallic glasses(MGs)have attracted extensive attention in the past decades due to their unique chem-ical,physical and mechanical properties promising for a wide range of engineering applications.A thor-ough understanding of their structure-property relationships is the key to the development of novel MGs with desirable performance.New strategies,as proposed by Materials Genome Initiative(MGI),construct a new paradigm for high-throughput materials discovery and design,and are being increas-ingly implemented in the search of new MGs.While a few reports have summarized the application of high-throughput and/or machine learning techniques,a comprehensive assessment of materials genome strategies for developing MGs is still missing.Herein,this paper aims to present a timely overview of key advances in this fascinating subject,as well as current challenges and future opportunities.A holistic approach is used to cover the related topics,including high-throughput preparation and characterization of MGs,and data-driven machine learning strategies for accelerating the development of novel MGs.Fi-nally,future research directions and perspectives for MGI-assisted design of MGs are also proposed and surmised.展开更多
Refractory high-entropy alloys have great potential to be utilized as high-temperature materials,and the repeatability and reproducibility of their mechanical properties are critical for practical applications.In this...Refractory high-entropy alloys have great potential to be utilized as high-temperature materials,and the repeatability and reproducibility of their mechanical properties are critical for practical applications.In this work,nevertheless,we found that the mechanical properties of the TiZrHfNb HEA greatly varied with the content of impurities in the samples even using high-purity raw materials.Specifically,the oxygen impurity is mainly responsible for the increment of the yield stress due to the strong interstitial hardening effect,whilst the ductility deterioration closely associates with the content of metalloid elements B,C,and Si.Our analysis reveals that the metalloid elements not only tend to segregate at grain boundaries but also enhance the aggregation of Zr and Ti.Such co-segregation induced the formation of strong(Zr,Ti)-metalloid bonds,resulting in grain boundary embrittlement and brittle fracture.Our current work demonstrates that the impurity contents in refractory HEAs need to be strictly controlled during production in order to improve their stability of mechanical performance.展开更多
Background Habitat degradation and flow regime alterations are two of the most prominent and common impact factors to freshwater mussel populations.Knowledge of the correlation between freshwater mussel distribution,d...Background Habitat degradation and flow regime alterations are two of the most prominent and common impact factors to freshwater mussel populations.Knowledge of the correlation between freshwater mussel distribution,density and habitat characteristics is important for maintaining and restoring their biodiversity and ecological functions.Information on predicting habitat suitability of freshwater mussels is lacking in China.Here,we aimed to analyze the correlation between freshwater mussel density and complex hydraulic and physicochemical variables to predict habitat suitability.Results The results showed that four complex hydraulic variables(boundary Reynolds number,critical shear stress,bed roughness and mean sediment particle size)and four physicochemical variables(water temperature,chlorophylla,transparency and pH)were key factors for predicting habitat suitability of freshwater mussels.Freshwater mussel density was significantly correlated with Froude number,water temperature and chlorophyll-a.Conclusions Our results confirmed that higher freshwater mussel density would be associated with areas that are stable in complex hydraulic and physicochemical variables.These results provide an important insight into the conservation of freshwater mussel diversity and their habitat restoration in China and globally.展开更多
Nanoporous metals have emerged as a new class of functional materials with unique structures and properties.Compared to conventional metals and alloys,nanoporous metals possess a high surface area,unique pore size dis...Nanoporous metals have emerged as a new class of functional materials with unique structures and properties.Compared to conventional metals and alloys,nanoporous metals possess a high surface area,unique pore size distribution and enhanced catalytic activity,making them highly desirable for a wide range of applications,such as photonics,sensing,supercapacitors and catalysis.In this review paper,we aim to summarize recent advances in the fabrication,structural regulation and functional applications of nanoporous metals and their composites via the dealloying of metallic glasses.Particularly,we will discuss the factors that affect the nanoporous structure,including precursor composition,dealloying conditions and post-treatment methods.We will also cover topics such as the preparation of immiscible nanoporous metals and the control of hierarchical nanoporous structures.Finally,we will provide a brief overview of the current situation and discuss the current challenges and potential research directions in the field.展开更多
In this paper, effects of cryogenic thermal cycling on deformation behavior and thermal stability of the Zr46Cu46AI8 bulk metallic glass （BMG） were studied. The results show that with the increase of the number of c...In this paper, effects of cryogenic thermal cycling on deformation behavior and thermal stability of the Zr46Cu46AI8 bulk metallic glass （BMG） were studied. The results show that with the increase of the number of cryogenic thermal cycles （CTC）, thermal stability remains almost unchanged, while the plasticity is increased, indicating that the cryogenic thermal cyclic treatment is an effective way to improve plasticity of metallic glasses without distinctly deteriorating thermal stability. Our analysis suggests that the increase in the defect density resulted from the cryogenic thermal treatments are responsible for the plasticity increment. Variation of yield strength can be well interpreted from microstructural percolation which affected by both density and characteristic volume of the defect sites.展开更多
In this letter,we briefly summarize experimental and theoretical findings of fo rmation and characterization of short-range orderings(SROs)as well as their effects on the defo rmation behavior of high-entropy alloys(H...In this letter,we briefly summarize experimental and theoretical findings of fo rmation and characterization of short-range orderings(SROs)as well as their effects on the defo rmation behavior of high-entropy alloys(HEAs).We show that existence of SROs is a common yet key structural feature of HEAs,and tuning the degree of SROs is an effective way for optimizing mechanical properties of HEAs.In additional,the challenges concerning about formation mechanism and characterization of SROs in HEAs are discussed,and future research activities in this regard are also proposed.展开更多
High-entropy ceramics (HECs) have attracted much attention due to their huge composition space,unique microstructure,and desirable properties.In contrast to previous studies,which have primarily focused on HECs with o...High-entropy ceramics (HECs) have attracted much attention due to their huge composition space,unique microstructure,and desirable properties.In contrast to previous studies,which have primarily focused on HECs with one anion,herein,we report a new family of ceramics with both multi-cationic and-anionic structures,i.e.,high-entropy carbide-nitrides (Ti0.33Zr0.33Hf0.33)(C0.5N0.5),(Ti0.25Zr0.25Hf0.25-Nb0.25)(C0.5N0.5) and (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)(C0.5N0.5).These as-synthesized HECs are mainly comprised of a face-centered cubic solid-solution phase accompanied by minor inevitable oxide phases.The formation mechanism of the solid-solution phase is discussed in terms of the lattice size difference and thermodynamic competition between configurational entropy and mixing enthalpy.It is found that the increment in the configurational entropy can effectively lower the sintering temperature and increase the fracture toughness.Particularly,the newly developed (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)(C0.5N0.5) exhibits a decent fracture toughness of 8.4 MPa m1/2and a low sintering temperature of 1750°C,making it promising for ultra-high temperature applications.Our work not only enriches knowledge regarding the HECs categories,but also opens a new pathway for developing HECs with multi-cationic and-anionic structures.展开更多
Fe-based metallic glasses(MGs)have been extensively investigated due to their unique properties,especially the outstanding soft-magnetic properties.However,conventional design of soft-magnetic Fe-based MGs is heavily ...Fe-based metallic glasses(MGs)have been extensively investigated due to their unique properties,especially the outstanding soft-magnetic properties.However,conventional design of soft-magnetic Fe-based MGs is heavily relied on“trial and error”experiments,and thus difficult to balance the saturation flux density(Bs)and thermal stability due to the strong interplay between the glass formation and magnetic interaction.Herein,we report an eXtreme Gradient Boosting(XGBoost)machine-learning(ML)model for developing advanced Fe-based MGs with a decent combination of Bs and thermal stability.展开更多
Searching for free-standing and cost-efficient hydrogen evolution reaction(HER)electrocatalysts with high efficiency and excellent durability remains a great challenge for the hydrogen-based energy industry.Here,we re...Searching for free-standing and cost-efficient hydrogen evolution reaction(HER)electrocatalysts with high efficiency and excellent durability remains a great challenge for the hydrogen-based energy industry.Here,we report fabrication of a unique hierarchically porous structure,i.e.,nanoporous Ni(NPN)/metallic glass(MG)composite,through surface dealloying of the specially designed Ni_(40)Zr_(40)Ti_(20)MG wire.This porous composite is composed of micrometer slits staggered with nanometer pores,which not only enlarges effective surface areas for the catalytic reaction,but also facilitates the release of H2 gas.As a result,the NPN/MG hybrid electrode exhibited the prominent HER performance with a low overpotential of 78 m V at 10 m A cm^(-2)and Tafel slope of 42.4 m V dec^(-1),along with outstanding stability in alkaline solutions.Outstanding catalytic properties,combining with their free-standing capability and cost efficiency,make the current composite electrode viable for HER applications.展开更多
In this study, mechanical tests were conducted oil a face-centered cubic FeCoNiCrMn high-entropy alloy, both in tension and compression, in a wide range of strain rates （10^-4-10^4 s^-1） to systematically investigat...In this study, mechanical tests were conducted oil a face-centered cubic FeCoNiCrMn high-entropy alloy, both in tension and compression, in a wide range of strain rates （10^-4-10^4 s^-1） to systematically investigate its dynamic response and underlying deformation mechanism. Materials with different grain sizes were tested to understand the effect of grain size, thus grain boundary volume, on the mechanical prop-erties. Microstructures of various samples both before and after deformation were examined using elec-tron backscatter diffraction and transmission electron microscopy. The dislocation structure as well as deformation-induced twins were analyzed and correlated with the measured mechanical properties. Plastic stability during tension of the current high-entropy alloy （HEA）, in particular, at dynamic strain rates, was discussed in lights of strain-rate sensitivity and work hardening rate. It was found that, under dynamic conditions, the strength and uniform ductility increased simultaneously as a result of the mas-sive formation of deformation twins. Specifically, an ultimate tensile strength of 734 MPa and uniform elongation of-63% are obtained at 2.3×10^3 s^-1, indicating that the alloy has great potential for energy absorption upon impact loading.展开更多
Because atoms in high-entropy alloys （HEAs） coordinate in very different and distorted local environ- ments in the lattice sites, even for the same type of constituent, their point defects could highly vary. Therefo...Because atoms in high-entropy alloys （HEAs） coordinate in very different and distorted local environ- ments in the lattice sites, even for the same type of constituent, their point defects could highly vary. Therefore, theoretical determination of the thermodynamic quantities （i.e., defect formation enthalpies） of various point defects is rather challenging because each corresponding thermodynamic quantity of all involve constituents is not unique. The knowledge of these thermodynamic quantities is prerequisite for designing novel HEAs and understanding the mechanical and physical behaviors of HEAs. However, to date there has not been a good method to theoretically derive the defect formation enthalpies of HEAs. Here, using first-principles calculations within the density functional theory （DFT） in combina- tion of special quasi-random structure models （SQSs）, we have developed a general method to derive corresponding formation enthalpies of point defects in HEAs, using vacancy formation enthalpies of a four-component equiatomic fcc-type FeCoCrNi HEA as prototypical and benchmark examples. In difference from traditional ordered alloys, the vacancy formation enthalpies of FeCoCrNi HEA vary in a highly wide range from 0.72 to 2.89 eV for Fe, 0.88-2.90 eV for Co, 0.78-3.09 eV for Cr, and 0.91-2.95 eV for Ni due to high-level site-to-site lattice distortions and compositional complexities. On average, the vacancy formation enthalpies of 1.58 eV for Fe, 1.61 eV for Cr, 1.70 eV for Co and 1.89 eV for Ni are all larger than that （1.41 eV） of pure fcc nickel. This fact implies that the vacancies are much more difficult to be created than in nickel, indicating a reasonable agreement with the recent experimental observation that FeCoCrNi exhibits two orders of amplitudes enhancement of radiation tolerance with the suppression of void formation at elevated temperatures than in pure nickel.展开更多
Since the Bronze Age to the early 21st century,development of metals and alloys have been limited to one principal element with minor addition of relatively small amounts of other elements,such as steels,titanium allo...Since the Bronze Age to the early 21st century,development of metals and alloys have been limited to one principal element with minor addition of relatively small amounts of other elements,such as steels,titanium alloys,aluminum alloys,and so on.Although a dozen of other elements may be added,conventional alloys展开更多
基金financially supported by the National Natural Science Foundation of China(Nos.51971017,52271003,52071024,52001184,and 52101188)the National Science Fund for distinguished Young Scholars,China(No.52225103)+3 种基金the Funds for Creative Research Groups of China(No.51921001)the National Key Research and Development Program of China(No.2022YFB4602101)the Projects of International Cooperation and Exchanges NSFC(No.52061135207)the Fundamental Research Funds for the Central Universities,China(No.FRF-TP-22-130A1)。
文摘Short-range ordering(SRO)is one of the most important structural features of high entropy alloys(HEAs).However,the chemical and structural analyses of SROs are very difficult due to their small size,complexed compositions,and varied locations.Transmission electron microscopy(TEM)as well as its aberration correction techniques are powerful for characterizing SROs in these compositionally complex alloys.In this short communication,we summarized recent progresses regarding characterization of SROs using TEM in the field of HEAs.By using advanced TEM techniques,not only the existence of SROs was confirmed,but also the effect of SROs on the deformation mechanism was clarified.Moreover,the perspective related to application of TEM techniques in HEAs are also discussed.
基金financially supported by the National Natural Science Foundation of China(Nos.52061135207,51871016,51921001,11790293,and 51971017)111 Project(No.B07003)the Projects of SKL-AMM-USTB(Nos.2019Z-01 and 2018Z-19)。
文摘The coupling effects of the metastable austenitic phase and the amorphous matrix in a transformation-induced plasticity(TRIP)-reinforced bulk metallic glass(BMG)composite under compressive loading were investigated by employing the digital image correlation(DIC)technique.The evolution of local strain field in the crystalline phase and the amorphous matrix was directly monitored,and the contribution from the phase transformation of the metastable austenitic phase was revealed.Local shear strain was found to be effectively consumed by the displacive phase transformation of the metastable austenitic phase,which relaxed the local strain/stress concentration at the interface and thus greatly enhanced the plasticity of the TRIP-reinforced BMG composites.Our current study sheds light on in-depth understanding of the underlying deformation mechanism and the interplay between the amorphous matrix and the metastable crystalline phase during deformation,which is helpful for design of advanced BMG composites with further improved properties.
基金National Natural Science Foundation of China(Nos.51971017,52271003,and 52071024)National Science Fund for Distinguished Young Scholars(No.52225103)+1 种基金Funds for Creative Research Groups of China(No.51921001)National Key Research and Development Program of China(No.2022YFB4602101).
文摘1.Introduction High entropy alloys(HEAs),arising from the incorporation of multiple principal elements[1,2],have garnered extensive atten-tion due to their great potential to be utilized under extreme con-ditions[3-5].
基金supported by the National Natural Science Foundation of China(Nos.52101120,52322102 and 51971018)the National Key Research and Development Program of China(No.2022YFB3705201).
文摘Producing ultrafine-grained(UFG)microstructures with enhanced thermal stability is an important yet challenging route to further improve mechanical properties of structural materials.Here,a high-performance bulk UFG copper that can stabilize even at temperatures up to 750℃(∼0.75 T m,T m is the melting point)was fabricated by manipulating its recrystallization behavior via low alloying of Co.Addition of 1 wt.%–1.5 wt.%of Co can trigger quick and copious intragranular clustering of Co atoms,which offers high Zener pinning pressure and pins the grain boundaries(GBs)of freshly recrystallized ul-trafine grains.Due to the fact that the subsequent growth of the coherent Co-enriched nanoclusters was slow,sufficient particles adjacent to GBs remained to inhibit the migration of GBs,giving rise to the UFG microstructure with prominently high thermal stability.This work manifests that the strategy for pro-ducing UFGs with coherent precipitates can be applied in many alloy systems such as Fe-and Cu-based,which paves the pathway for designing advanced strain-hardenable UFGs with plain compositions.
基金supported by the National Natural Science Foundation of China(Nos.11790293,51871016,51671021,51971017,52122408,52071023,51901013)the Funds for Creative Research Groups of China(51921001)+3 种基金111 Project(BP0719004)Program for Changjiang Scholars and Innovative Research Team in University of China(IRT_14R05)financial support from the Fundamental Research Funds for the Central Universities of China(No.FRF-TP-18-004C1,No.FRF-BD-19-002B,respectively)financial support from Projects of SKLAMM-USTB(2019Z-01,2018-Z01,2022Z-09).
文摘Alloys with a hexagonal close-packed(HCP)lattice often suffer from intrinsic brittleness due to their in-sufficient number of slip systems,which limits their practical uses.In this paper,nevertheless,we show that remarkably tensile ductility in HCP Hf-Zr-Ti medium entropy alloys(MEAs)was achieved,particu-larly in the MEAs with a higher content of Hf.Both first-principles calculation and experimental analyses reveal that addition of Hf increases basal I2 stacking fault energy and decreases prismatic stacking fault energy in these HCP MEAs,which promotes the source of pyramidal dislocations due to the facilitated cross slips of basal dislocations and eventually give rise to the observed large tensile ductility.Our current findings not only shed new insights into understanding deformation of HCP alloys,but also provide a basis for controlling alloying effects for developing novel HCP complex alloys with optimized properties.
基金This work was financially supported by the National Natural Science Foundation of China(Nos.51671021,11790293,51871016,52071024,and 51961160729)the Funds for Creative Research Groups of China(No.51921001)+1 种基金the 111 Project(No.B07003)the Fundamental Research Funds for the Central Universities.
文摘Multi-principal element alloys(MPEAs)have attracted much attention as future nuclear materials due to their extraordinary radiation resistances.In this work,we have elucidated the development of local chemical orderings(LCOs)and their influences on radiation damage behavior in the typical CrFeNi MPEA by hybrid-molecular dynamics and Monte Carlo simulations.It was found that considerable LCOs consist-ing of the Cr-Cr and Ni-Fe short-range orders existed in the ordered configuration with optimized system energy.Through modeling the accumulation cascades up to 1000 recoils,we revealed that the size of de-fect clusters and dislocation loops is smaller in the ordered configuration than those in the random one,although the former formed more Frenkel pairs(i.e.,self-interstitials and vacancies).In addition,the dis-tribution of dislocation loops is relatively more dispersed in the ordered configuration,and the stair-rod dislocations related to irradiation swelling are also smaller,implying that the existence of LCOs is con-ducive to enhancing radiation damage tolerance.To understand the underlying mechanism,the effects of LCOs on the formation and evolution of defects and radiation resistance were discussed from the aspects of atomic bonding,migration path,and energy of defect diffusion,which provides theoretical guidance for the design of MPEAs with enhanced radiation resistance.
基金This research was supported financially by National Natural Sci-ence Foundation of China(Nos.52130108,51961160729,51871016,11790293,52071024)Guangdong Basic and Applied Basic Research Foundation(Nos.2020B1515120077 and2022A1515110805)+3 种基金the Funds for Creative Research Groups of China(No.51921001)Program for Changjiang Scholars and Innovative Research Team in University of China(No.IRT_14R05)the Fundamental Research Fund for the Central Universities(No.FRF-TP-22-001C2)State Key Lab of Advanced Metals and Materials(No.2022-ZD01).
文摘Metallic glasses(MGs)have attracted extensive attention in the past decades due to their unique chem-ical,physical and mechanical properties promising for a wide range of engineering applications.A thor-ough understanding of their structure-property relationships is the key to the development of novel MGs with desirable performance.New strategies,as proposed by Materials Genome Initiative(MGI),construct a new paradigm for high-throughput materials discovery and design,and are being increas-ingly implemented in the search of new MGs.While a few reports have summarized the application of high-throughput and/or machine learning techniques,a comprehensive assessment of materials genome strategies for developing MGs is still missing.Herein,this paper aims to present a timely overview of key advances in this fascinating subject,as well as current challenges and future opportunities.A holistic approach is used to cover the related topics,including high-throughput preparation and characterization of MGs,and data-driven machine learning strategies for accelerating the development of novel MGs.Fi-nally,future research directions and perspectives for MGI-assisted design of MGs are also proposed and surmised.
基金financially supported by the Funds for Creative Research Groups of China(51921001)the 111 Project(BP0719004)+1 种基金the Program for Changjiang Scholars,Innovative Research Team in University of China(IRT_14R05)the National Natural Science Foundation of China(11790293 and 51871016)。
基金This research was financially supported by the National Natural Science Foundation of China(Nos.11790293,52225103,51871016,52271003,52071023,52122408,and 52225103)the Funds for Creative Research Groups of China(No.51921001)+2 种基金Project of International Cooperation and Exchanges NSFC(No.52061135207,51961160729)National Key Research and Development Program of China(2022YFB4602101)Joint Project of NSFC(No.U20B2025111).
文摘Refractory high-entropy alloys have great potential to be utilized as high-temperature materials,and the repeatability and reproducibility of their mechanical properties are critical for practical applications.In this work,nevertheless,we found that the mechanical properties of the TiZrHfNb HEA greatly varied with the content of impurities in the samples even using high-purity raw materials.Specifically,the oxygen impurity is mainly responsible for the increment of the yield stress due to the strong interstitial hardening effect,whilst the ductility deterioration closely associates with the content of metalloid elements B,C,and Si.Our analysis reveals that the metalloid elements not only tend to segregate at grain boundaries but also enhance the aggregation of Zr and Ti.Such co-segregation induced the formation of strong(Zr,Ti)-metalloid bonds,resulting in grain boundary embrittlement and brittle fracture.Our current work demonstrates that the impurity contents in refractory HEAs need to be strictly controlled during production in order to improve their stability of mechanical performance.
基金supported by the National Key R&D Program of China(2018YFD0900801)Educational Commission of Guangdong Province of China(2021ZDZX4054).
文摘Background Habitat degradation and flow regime alterations are two of the most prominent and common impact factors to freshwater mussel populations.Knowledge of the correlation between freshwater mussel distribution,density and habitat characteristics is important for maintaining and restoring their biodiversity and ecological functions.Information on predicting habitat suitability of freshwater mussels is lacking in China.Here,we aimed to analyze the correlation between freshwater mussel density and complex hydraulic and physicochemical variables to predict habitat suitability.Results The results showed that four complex hydraulic variables(boundary Reynolds number,critical shear stress,bed roughness and mean sediment particle size)and four physicochemical variables(water temperature,chlorophylla,transparency and pH)were key factors for predicting habitat suitability of freshwater mussels.Freshwater mussel density was significantly correlated with Froude number,water temperature and chlorophyll-a.Conclusions Our results confirmed that higher freshwater mussel density would be associated with areas that are stable in complex hydraulic and physicochemical variables.These results provide an important insight into the conservation of freshwater mussel diversity and their habitat restoration in China and globally.
基金supported by the National Natural Science Foundation of China(Nos.52071024,52271003,52101188)the Funds for Creative Research Groups of NSFC(51921001)+3 种基金the Projects of International Cooperation and Exchanges of NSFC(51961160729,52061135207)the 111 Project(BP0719004)the Program for Changjiang Scholars and Innovative Research Team in University of China(IRT_14R05)the Fundamental Research Fund for the Central Universities of China(FRF-TP-22-005C2).
文摘Nanoporous metals have emerged as a new class of functional materials with unique structures and properties.Compared to conventional metals and alloys,nanoporous metals possess a high surface area,unique pore size distribution and enhanced catalytic activity,making them highly desirable for a wide range of applications,such as photonics,sensing,supercapacitors and catalysis.In this review paper,we aim to summarize recent advances in the fabrication,structural regulation and functional applications of nanoporous metals and their composites via the dealloying of metallic glasses.Particularly,we will discuss the factors that affect the nanoporous structure,including precursor composition,dealloying conditions and post-treatment methods.We will also cover topics such as the preparation of immiscible nanoporous metals and the control of hierarchical nanoporous structures.Finally,we will provide a brief overview of the current situation and discuss the current challenges and potential research directions in the field.
基金supported by the National Natural Science Foundation of China(51671018,11790293,51531001,51422101,51371003,and 51671021)111 Project(B07003)+3 种基金International S&T Cooperation Program of China(2015DFG52600)Program for Changjiang Scholars and Innovative Research Team in University of China(IRT_14R05)the Projects of SKLAMM-USTB(2016Z04,2016-09,2016Z-16)the financial support from the Top-Notch Young Talents Program and Fundamental Research Fund for the Central Universities(FRF-TP-15-004C1)
文摘In this paper, effects of cryogenic thermal cycling on deformation behavior and thermal stability of the Zr46Cu46AI8 bulk metallic glass （BMG） were studied. The results show that with the increase of the number of cryogenic thermal cycles （CTC）, thermal stability remains almost unchanged, while the plasticity is increased, indicating that the cryogenic thermal cyclic treatment is an effective way to improve plasticity of metallic glasses without distinctly deteriorating thermal stability. Our analysis suggests that the increase in the defect density resulted from the cryogenic thermal treatments are responsible for the plasticity increment. Variation of yield strength can be well interpreted from microstructural percolation which affected by both density and characteristic volume of the defect sites.
基金supported by the National Natural Science Foundation of China(Nos.51921001,51871016,51971017,51531001,51901013,and 51671021)111 Project(B07003)+3 种基金Program for Changjiang Scholars and Innovative Research Team in University of China(IRT-14R05)the Projects of SKLAMM-USTBthe financial support from the Fundamental Research Fund for the Central Universities(No.FRF-BD-19002B)National Key Basic Research Program,China(No.2016YFB0300502)。
文摘In this letter,we briefly summarize experimental and theoretical findings of fo rmation and characterization of short-range orderings(SROs)as well as their effects on the defo rmation behavior of high-entropy alloys(HEAs).We show that existence of SROs is a common yet key structural feature of HEAs,and tuning the degree of SROs is an effective way for optimizing mechanical properties of HEAs.In additional,the challenges concerning about formation mechanism and characterization of SROs in HEAs are discussed,and future research activities in this regard are also proposed.
基金supported by the National Natural Science Foundation of China (51671021,51961160729,1179029,51871016 and 51971017)the Funds for Creative Research Groups of China (51921001)+3 种基金111 Project (B07003)the Program for Changjiang Scholars and Innovative Research Team in University of China (IRT14R05)the Project of SKLAMM-USTB (2019Z-01)the Project supported by the State Key Laboratory of Powder Metallurgy,Central South University,Changsha,China。
文摘High-entropy ceramics (HECs) have attracted much attention due to their huge composition space,unique microstructure,and desirable properties.In contrast to previous studies,which have primarily focused on HECs with one anion,herein,we report a new family of ceramics with both multi-cationic and-anionic structures,i.e.,high-entropy carbide-nitrides (Ti0.33Zr0.33Hf0.33)(C0.5N0.5),(Ti0.25Zr0.25Hf0.25-Nb0.25)(C0.5N0.5) and (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)(C0.5N0.5).These as-synthesized HECs are mainly comprised of a face-centered cubic solid-solution phase accompanied by minor inevitable oxide phases.The formation mechanism of the solid-solution phase is discussed in terms of the lattice size difference and thermodynamic competition between configurational entropy and mixing enthalpy.It is found that the increment in the configurational entropy can effectively lower the sintering temperature and increase the fracture toughness.Particularly,the newly developed (Ti0.2Zr0.2Hf0.2Nb0.2Ta0.2)(C0.5N0.5) exhibits a decent fracture toughness of 8.4 MPa m1/2and a low sintering temperature of 1750°C,making it promising for ultra-high temperature applications.Our work not only enriches knowledge regarding the HECs categories,but also opens a new pathway for developing HECs with multi-cationic and-anionic structures.
基金This research was supported by National Natural Science Foundation of China(Nos.51671018,51671021,51531001,11790923,and 51961160729)the Funds for Creative Research Groups of China(No.51921001),Program for Changjiang Scholars and Innovative Research Team in University of China(No.IRT_14R05)+3 种基金National Key Basic Research Program China(No.2016YFB0300502)the Fundamental Research Fund for the Central Universities(Nos.FRF-GF-19-011A and FRF-BD-19-002B)X.J.L.is grateful to the financial support from the Projects of SKLAMM-USTB(2018Z-19)HXL appreciates the financial support from the Natural Science Foundation of Beijing,China(Grant No.2202033).
文摘Fe-based metallic glasses(MGs)have been extensively investigated due to their unique properties,especially the outstanding soft-magnetic properties.However,conventional design of soft-magnetic Fe-based MGs is heavily relied on“trial and error”experiments,and thus difficult to balance the saturation flux density(Bs)and thermal stability due to the strong interplay between the glass formation and magnetic interaction.Herein,we report an eXtreme Gradient Boosting(XGBoost)machine-learning(ML)model for developing advanced Fe-based MGs with a decent combination of Bs and thermal stability.
基金supported by National Natural Science Foundation of China(Nos.11790293,51871016,51671018,51671021,and 51961160729)the Funds for Creative Research Groups of China(No.51921001)+3 种基金111 Project(B07003)the Program for Changjiang Scholars and Innovative Research Team in University of China(IRT 14R05)the Fundamental Research Funds for the Central Universities(Nos.FRF-GF-19-011A,FRF-TP-18-004C1,FRF-BD-19-002B,and FRF-TP19-054A2)partially supported by State Key Laboratory for Advanced Metals and Materials(2018Z-19)。
文摘Searching for free-standing and cost-efficient hydrogen evolution reaction(HER)electrocatalysts with high efficiency and excellent durability remains a great challenge for the hydrogen-based energy industry.Here,we report fabrication of a unique hierarchically porous structure,i.e.,nanoporous Ni(NPN)/metallic glass(MG)composite,through surface dealloying of the specially designed Ni_(40)Zr_(40)Ti_(20)MG wire.This porous composite is composed of micrometer slits staggered with nanometer pores,which not only enlarges effective surface areas for the catalytic reaction,but also facilitates the release of H2 gas.As a result,the NPN/MG hybrid electrode exhibited the prominent HER performance with a low overpotential of 78 m V at 10 m A cm^(-2)and Tafel slope of 42.4 m V dec^(-1),along with outstanding stability in alkaline solutions.Outstanding catalytic properties,combining with their free-standing capability and cost efficiency,make the current composite electrode viable for HER applications.
基金supported by the National Natural Science Foundation of China(51671018,51531001,51422101,51371003,and 51671021)111 Project(B07003)+5 种基金International S&T Cooperation Program of China(2015DFG52600)Program for Changjiang Scholars and Innovative Research Team in University of China(IRT_14R05)the Projects of SKL-AMM-USTB(2016Z-04,2016-09,2016Z-16)the financial support from the Top-Notch Young Talents Programthe Fundamental Research Funds for the Central Universitiesthe financial support by US-NSF under contract DMR-1408722
文摘In this study, mechanical tests were conducted oil a face-centered cubic FeCoNiCrMn high-entropy alloy, both in tension and compression, in a wide range of strain rates （10^-4-10^4 s^-1） to systematically investigate its dynamic response and underlying deformation mechanism. Materials with different grain sizes were tested to understand the effect of grain size, thus grain boundary volume, on the mechanical prop-erties. Microstructures of various samples both before and after deformation were examined using elec-tron backscatter diffraction and transmission electron microscopy. The dislocation structure as well as deformation-induced twins were analyzed and correlated with the measured mechanical properties. Plastic stability during tension of the current high-entropy alloy （HEA）, in particular, at dynamic strain rates, was discussed in lights of strain-rate sensitivity and work hardening rate. It was found that, under dynamic conditions, the strength and uniform ductility increased simultaneously as a result of the mas-sive formation of deformation twins. Specifically, an ultimate tensile strength of 734 MPa and uniform elongation of-63% are obtained at 2.3×10^3 s^-1, indicating that the alloy has great potential for energy absorption upon impact loading.
基金supported by the National Science Fund for Distinguished Young Scholars (No. 51725103)by the National Natural Science Foundation of China (Grant Nos. 51671193 and 51474202)+7 种基金by the Science Challenging (Project No. TZ2016004)by the “Hundred Talented Project” of the Chinese Academy of Sciencesfinancially supported by the National Natural Science Foundation of China (Nos. 51671018 and 51671021)111 Project (No. B07003)International S&T Cooperation Program of China (No. 2015DFG52600)the Program for Changjiang Scholars and Innovative Research Team in University of China (No. IRT 14R05)the Projects of SKL-AMM-USTB (Nos. 2016Z-04, 2016-09 and 2016Z-16)supported by the Hong Kong URC grant under the contract with City University of Hong Kong
文摘Because atoms in high-entropy alloys （HEAs） coordinate in very different and distorted local environ- ments in the lattice sites, even for the same type of constituent, their point defects could highly vary. Therefore, theoretical determination of the thermodynamic quantities （i.e., defect formation enthalpies） of various point defects is rather challenging because each corresponding thermodynamic quantity of all involve constituents is not unique. The knowledge of these thermodynamic quantities is prerequisite for designing novel HEAs and understanding the mechanical and physical behaviors of HEAs. However, to date there has not been a good method to theoretically derive the defect formation enthalpies of HEAs. Here, using first-principles calculations within the density functional theory （DFT） in combina- tion of special quasi-random structure models （SQSs）, we have developed a general method to derive corresponding formation enthalpies of point defects in HEAs, using vacancy formation enthalpies of a four-component equiatomic fcc-type FeCoCrNi HEA as prototypical and benchmark examples. In difference from traditional ordered alloys, the vacancy formation enthalpies of FeCoCrNi HEA vary in a highly wide range from 0.72 to 2.89 eV for Fe, 0.88-2.90 eV for Co, 0.78-3.09 eV for Cr, and 0.91-2.95 eV for Ni due to high-level site-to-site lattice distortions and compositional complexities. On average, the vacancy formation enthalpies of 1.58 eV for Fe, 1.61 eV for Cr, 1.70 eV for Co and 1.89 eV for Ni are all larger than that （1.41 eV） of pure fcc nickel. This fact implies that the vacancies are much more difficult to be created than in nickel, indicating a reasonable agreement with the recent experimental observation that FeCoCrNi exhibits two orders of amplitudes enhancement of radiation tolerance with the suppression of void formation at elevated temperatures than in pure nickel.
文摘Since the Bronze Age to the early 21st century,development of metals and alloys have been limited to one principal element with minor addition of relatively small amounts of other elements,such as steels,titanium alloys,aluminum alloys,and so on.Although a dozen of other elements may be added,conventional alloys
