A series of Al-xSi-yGe filler metals(x=4–12 and y=10–40,wt%)were prepared,and the effect of Si and Ge on microstructure and melting characteristics of filler metals was studied.The thermodynamic model of Al-Si-Ge te...A series of Al-xSi-yGe filler metals(x=4–12 and y=10–40,wt%)were prepared,and the effect of Si and Ge on microstructure and melting characteristics of filler metals was studied.The thermodynamic model of Al-Si-Ge ternary alloy was established to analyze the phase formation mechanism of filler metals based on Miedema model,Tanaka model,and Toop equation.This research provided a basis for the composition optimization of filler metals and the analysis of metallurgical reaction process between filler metals and base materials.Results show that Al-Si-Ge alloy is composed of Al-Ge eutectic phase,Al-Si eutectic phase,and primary Si.Ge addition promotes the precipitation of primary Si.Ge is the main melting point depressant element of filler metals.With the increase in Ge content from 10wt%to 40wt%,the solid phase line of filler metals remains unchanged,whereas the liquidus temperature decreases from 567.65°C to 499.96°C.With the increase in Ge content of filler metal,Ge content in eutectic Si phase is increased,the endothermic peak of Al-Si eutectic reaction according to thermogravimetry curve becomes smoother,and Al-Si eutectic temperature is decreased.Ge addition can reduce the free energy of Al-Si alloy system.The lowest point of free energy is located on Al-Ge side.The eutectic Ge phase with the composition similar to pure Ge composition is the most likely to appear in the microstructure of filler metals,whereas the eutectic Si phase with the composition similar to pure Si composition is the least likely to appear.The thermodynamic calculation results are consistent with the experiment results.展开更多
Cr_(2)AlC,a representative MAX phase,gains increasing attention for the excellent oxidation tolerance and corrosion resistance used in harsh high temperature and strong radiation environments.However,the lack of the p...Cr_(2)AlC,a representative MAX phase,gains increasing attention for the excellent oxidation tolerance and corrosion resistance used in harsh high temperature and strong radiation environments.However,the lack of the phase formation mechanism has become the key bottleneck to the practical applications for Cr_(2)AlC synthesis with high purity at low temperatures.In this work,we fabricated the amorphous Cr-Al-C coating by a hybrid magnetron sputtering/cathodic arc deposition technique,in which the in-situ heating transmission electron microscopy(TEM)was conducted in a temperature range of 25-650℃ to address the real-time phase transformation for Cr_(2)AlC coating.The results demonstrated that increas-ing the temperature from 25 to 370℃ led to the structural transformation from amorphous Cr-Al-C to the crystalline Cr_(2)Al interphases.However,the high-purity Cr_(2)AlC MAX phase was distinctly formed at 500℃,accompanied by the diminished amorphous feature.With the further increase of temperature to 650℃,the decomposition of Cr_(2)AlC to Cr_(7)C_(3)impurities was observed.Similar phase evolution was also evidenced by the Ab-initio molecular dynamics calculations,where the bond energy of Cr-Cr,Cr-Al,and Cr-C played the key role in the formed crystalline stability during the heating process.The observa-tions not only provide fundamental insight into the phase formation mechanism for high-purity Cr_(2)AlC coatings but also offer a promising strategy to manipulate the advanced MAX phase materials with high tolerance to high-temperature oxidation and heavy ion radiations.展开更多
YAG： Ce^3 ＋ phosphor particles were prepared using polyacrylamide gel method. The structure evolution of powders during annealing process was followed by X-ray diffraction determination. It is found that some interm...YAG： Ce^3 ＋ phosphor particles were prepared using polyacrylamide gel method. The structure evolution of powders during annealing process was followed by X-ray diffraction determination. It is found that some intermediate phases, including θ-Al2O3, YAM and YAP, are formed when calcining polyacrylamide gel, however, the pure YAG phase can be formed directly when calcining polyacrylamide gel with α-Al2O3 as seed crystal. These facts show that the existence of α- Al2O3 seed crystal can block the formation of θ-Al2O3, YAM and YAP, and accelerate its reaction with Y2O3 to form YAG phase directly at lower temperature. The emission peak of prepared YAG ： Ce^3 ＋ phosphor is wide with maximum at 550 nm and the exitation band has two peaks, the major one is around at 460 nm, which matches the blue emission of GaN LED and is suitable for the assemble of white LED. Some fluxes can enhance the photoluminescence intensity of phosphor particles, that can be attributed both to the improvement of crystallization processes of YAG and to the stabilization of trivalence cerium ion in YAG：Ce^3 ＋.展开更多
The effect of wheel speed on phase formation and magnetic properties of （Ndo.4La0.6）lsFeTzsBzs and （Ndo.4La0.6）13.4Fe79.9B6.7 ribbons prepared by melt-spinning method was investigated experimentally. Based on X-ra...The effect of wheel speed on phase formation and magnetic properties of （Ndo.4La0.6）lsFeTzsBzs and （Ndo.4La0.6）13.4Fe79.9B6.7 ribbons prepared by melt-spinning method was investigated experimentally. Based on X-ray diffraction results, all melt-spun ribbons consist of the main phase with the tetragonal 2：14：1 type structure and the minor α-Fe phase. Magnetic measurements show the maximum magnetic energy product （（BH）max） and the remanence （Mr） increases firstly and then decreases with the increase of wheel speed, while the coercivity （Hci） increases, resulting from the variation of the average volume fraction of the ^-Fe phase and the average grain size in the melt-spun ribbons. Using Henkel plots, the interaction between the 2：14：1 phase and the ^-Fe phase in the melt-spun ribbons was analyzed and the intergranular exchange coupling is manifested. Optimal magnetic properties of Hci - 7.27 kOe, Mr - 90.94 emu/g and （BH）max -- 12.10 MGOe are achieved in the （Ndo.4La0.6）lsFeTzsBT.s ribbon with the wheel speed of 26 m/s. It indicates that magnetic properties of Nd-Fe-B melt-spun ribbons with highly abundant rare earth element La can be improved by optimizing alloy composition and preparation process.展开更多
This paper characterises and evaluates Si_(3)N_(4)/Ti composites during thermal treatment using an in situ neutron diffraction technique.The composites were developed using a conventional press and sinter technique.Pu...This paper characterises and evaluates Si_(3)N_(4)/Ti composites during thermal treatment using an in situ neutron diffraction technique.The composites were developed using a conventional press and sinter technique.Pure titanium(Ti)was chosen as the matrix,and different concentrations of Si_(3)N_(4)were used as the reinforcement.The effects of sintering temperature and the concentration of Si_(3)N_(4)in the Ti matrix were investigated with respect to phase constituents.The Si_(3)N_(4)mass fraction in the Ti matrix was found to be the key parameter for the reaction.Because of its instability in Ti at higher temperatures,in situ reactions between the reinforcing particles and matrix led to the formation of intermetallic compounds,such as Ti_(5)Si_(3)and possibly Ti3Si,in the composites containing higher weight fractions of Si_(3)N_(4).展开更多
Boiling and fouling are taken as typical examples of new phase formation process to be analyzed and discussed in this paper. The process dynamics of nucleate boiling is analyzed and its mechanism is discussed from the...Boiling and fouling are taken as typical examples of new phase formation process to be analyzed and discussed in this paper. The process dynamics of nucleate boiling is analyzed and its mechanism is discussed from the view point of self-organization. Fouling, which is a more complicated phenomenon of new phase formation, involves series of underlying processes. The morphology and fractal analysis of fouling on low-energy surface and that with fouling inhibitors are studied and discussed. It is suggested that considering the process dynamics, fractal analysis and self-organization, a new avenue of research should be found.展开更多
Big-data analysis of phase-formation rules of high-entropy alloys（HEAs）was conducted and a phase formation rule from a dynamic view was deduced.It was indicated in literatures that cooling rate has a strong influenc...Big-data analysis of phase-formation rules of high-entropy alloys（HEAs）was conducted and a phase formation rule from a dynamic view was deduced.It was indicated in literatures that cooling rate has a strong influence on the phase formation of HEAs.Higher cooling rate may promote the generation of amorphous phase,and accordingly suppress the formation of intermetallics.Meanwhile,it was also shown that cooling rate had little impact on the formation of solid-solution phase.To demonstrate this rule,a series of FeCoNi（AlSiB）xHEAs ribbons were fabricated by a melt-spinning technique,and the microstructure,mechanical,and magnetic properties were also investigated.The results show that all ribbons exhibit disordered solid-solution structure.The addition of boron changes the alloy from ductility to brittleness,but without evident change of magnetic properties.The alloy in the nominal composition of FeCoNi（AlSi）0.2has the best combination of mechanical and magnetic properties.A distinct feature of HEAs in magnetization was noticed and explained.展开更多
After corrosion and pitting corrosion, the wire nanometer phases are observed using a transmission electron microscope (TEM) in C+Ti dual implanted H13 steel. The property of corrosion resistance dual-implanted (C+Ti)...After corrosion and pitting corrosion, the wire nanometer phases are observed using a transmission electron microscope (TEM) in C+Ti dual implanted H13 steel. The property of corrosion resistance dual-implanted (C+Ti) H13 steel is studied using multi-sweep cyclic voltammetry. TEM images of the cross section of an implanted sample reveal plenty of circular nanometer structures with diameters of 10–30 nm. The phases are densely embedded in the implanted layer. The embedded structure improves the surface corrosion resistance, as can be observed with a scanning electron microscope (SEM). The phases with the shape of a tiny wire in nanometer size are formed. The nanometer phases, consisting of TiC, FeTi and FeTi2, are formed in dual implanted layer. The corrosion current peak density decreases to 1/16–1/10 that of the unimplanted H13 steel. The formation conditions of the nanometer phases and their effects are investigated. The passivation layer consists of nanometer phases. The corrosion resistance of the dual implantation can be further enhanced with an increase in ion dose.展开更多
A novel approach for fabricating multi-principal element alloys with adjustable phase configurations and mechanical properties was developed using laser-aided additive manufacturing(LAAM),combining FCC-structured(face...A novel approach for fabricating multi-principal element alloys with adjustable phase configurations and mechanical properties was developed using laser-aided additive manufacturing(LAAM),combining FCC-structured(face-centered cubic)CoCrNi and BCC-structured(body-centered cubic)CoCrNiAl0.6TiFe feedstocks.During fabrication,CoCrNi powders and CoCrNiAl0.6TiFe powders were simultaneously fed into the melt pool at individually adjustable rates,allowing for controlled phase transitions.The resulting phase evolution demonstrated a gradual transition from a single FCC structure CoCrNi(A10.6TiFe)x(x=0,0.1,0.2,0.3)to a dual FCCB2 structure CoCrNi(Al0.6TiFe)x(x=0.4,0.5)as the proportion of BCC-structured powders increased.The B2 phase,enriched in Ti and Al due to their larger atomic radii and negative segregation enthalpy,precipitated around the FCC matrix,with volume fractions of 0.5%and 5.7%for CoCrNi(A10.6TiFe)0.4 and CoCrNi(A10.6TiFe)0.5,respectively.This phase transition resulted in significant mechanical enhancements.Yield and ultimate tensile strengths increased from 486.0 and 781.2 MPa(CoCrNi)to 887.2 and 1165.2 MPa(CoCrNi(A10.6TiFe)0.5).Dislocation-mediated hardening prevailed in single-phase FCC alloys,exhibiting a characteristic dislocation density of 2.5×10^(15)m^(-2)for CoCrNi(A10.6TiFe)0.3 alloy.Once the B2 phase precipitated,precipitation strengthening became dominant,as observed in transmission electron microscopy(TEM),where dislocations accumulated around B2 precipitates.This study presents an innovative alloy fabrication strategy that enables precise tuning of FCC-BCC dualphase structures,facilitating the direct fabrication of components with spatially customized properties.These findings provide valuable insights for developing multiprincipal element alloys with heterogeneous microstructures for advanced engineering applications.展开更多
Shale gas has currently attracted much attention during oil and gas exploration and development. Fractures in shale have an important influence on the enrichment and preservation of shale gas. This work studied the de...Shale gas has currently attracted much attention during oil and gas exploration and development. Fractures in shale have an important influence on the enrichment and preservation of shale gas. This work studied the developmental period and formation mechanism of tectonic fractures in the Longmaxi Formation shale in the Dingshan area of southeastern Sichuan Basin based on extensive observations of outcrops and cores, rock acoustic emission(Kaiser) experiments, homogenization temperature of fracture fill inclusions, apatite fission track, thermal burial history. The research shows that the fracture types of the Longmaxi Formation include tectonic fractures, diagenetic fractures and horizontal slip fractures. The main types are tectonic high-angle shear and horizontal slip fractures, with small openings, large spacing, low densities, and high degrees of filling. Six dominant directions of the fractures after correction by plane included NWW, nearly SN, NNW, NEE, nearly EW and NW. The analysis of field fracture stage and fracture system of the borehole suggests that the fractures in the Longmaxi Formation could be paired with two sets of plane X-shaped conjugate shear fractures, i.e., profile X-shaped conjugate shear fractures and extension fractures. The combination of qualitative geological analysis and quantitative experimental testing techniques indicates that the tectonic fractures in the Longmaxi Formation have undergone three periods of tectonic movement, namely mid-late Yanshanian movement(82–71.1 Ma), late Yanshanian and middle Himalaya movements(71.1–22.3 Ma), and the late Himalayan movement(22.3–0 Ma). The middle-late period of the Yanshanian movement and end of the Yanshanian movement-middle period of the Himalayan movement were the main fractureforming periods. The fractures were mostly filled with minerals, such as calcite and siliceous. The homogenization temperature of fracture fill inclusions was high, and the paleo-stress value was large; the tectonic movement from the late to present period was mainly a slight transformation and superposition of existing fractures and tectonic systems. Based on the principle of tectonic analysis and theory of geomechanics, we clarified the mechanism of the fractures in the Longmaxi Formation, and established the genetic model of the Longmaxi Formation. The research on the qualitative and quantitative techniques of the fracture-phase study could be effectively used to analyze the causes of the marine shale gas fractures in the Sichuan Basin. The research findings and results provide important references and technical support for further exploration and development of marine shale gas in South China.展开更多
Elemental powders of Cu and Fe were ball milled for various time durations up to 100 h. The various stages of forced alloying by ball milling, leading to instability of elemental crystalline phases and formation of qu...Elemental powders of Cu and Fe were ball milled for various time durations up to 100 h. The various stages of forced alloying by ball milling, leading to instability of elemental crystalline phases and formation of quasicrystalline phases were monitored using X-ray diffraction. Diffusion of Fe into the Cu matrix is proposed as the cause which triggers the instability of crystalline phases and leads to the formation of quasicrystalline phases after 10 h of milling. Milling for 100 h resulted in two different quasicrystalline phases with different lattice constants. Role of the nanocrystalline microstructure as an important criterion for the destabilisation of crystalline phases is explained. It is suggested that the formation of nanocrystalline microstructure and their subsequent transformation into quasicrystalline phases may be associated with a continuous increase in the disclination content of the system, which had formed as a result of continued milling and mechanical deformation.展开更多
A novel low-activation Ti_(1.5)ZrV_(0.5)Ta_(0.5)refractory high-entropy alloy(RHEA)was designed as a potential candidate for nuclear reactor application.At room temperature,it had an elongation of 8.4%and a yield stre...A novel low-activation Ti_(1.5)ZrV_(0.5)Ta_(0.5)refractory high-entropy alloy(RHEA)was designed as a potential candidate for nuclear reactor application.At room temperature,it had an elongation of 8.4%and a yield strength of 1096 MPa.The phase evolution of this alloy and its effect on properties was investigated.At 400℃,the solid solution bcc 1 transformed into the fcc phase and bcc 2 phase,and theωphase andαphase also appeared.At 600℃,theωphase andαphase disappeared,and the microstructure of the alloy was composed of the fcc phase and bcc 2 phase.When the temperature was up to 1200℃,the fcc phase and bcc 2 phase re-transformed into solid solution bcc 1 phase.The precipitation ofωphase andαphase caused a sharp increase in strength and a decrease in plasticity.Meanwhile,the appearance of the fcc phase led to a simultaneous decrease in strength and ductility,due to larger stress concentrations at the fcc/bcc interface.Besides,the formation mechanism of each phase in the alloy was discussed in detail.展开更多
For the first time, DySrA104 of K2NiF4-type structure was synthesized. The parameters of DySrA104 ele- mentary unit cell are determined as follows： a = 0.368 （4） nm, c = 1.229 （2） nm, V = 0.166 （4） nm3. The res...For the first time, DySrA104 of K2NiF4-type structure was synthesized. The parameters of DySrA104 ele- mentary unit cell are determined as follows： a = 0.368 （4） nm, c = 1.229 （2） nm, V = 0.166 （4） nm3. The research of the complex aluminates ZnSrA104 （Ln = Nd, Gd, Dy） solid-state process demonstrated the change of the formation mecha- nism among LnSrA104 （Ln = Nd, Gd, Dy） series from DySrA104 oxide. The performed analysis provided a possibility to realize why chemists couldn＇t get DySrA104 for a long period of time.展开更多
The influence of polyepoxysuccinic acid（PESA）on the solid phase products in hydrated Portland cement pastes was investigated by isothermal calorimetry,X-ray diffraction（XRD）,^29Si and ^27Al nuclear magnetic resona...The influence of polyepoxysuccinic acid（PESA）on the solid phase products in hydrated Portland cement pastes was investigated by isothermal calorimetry,X-ray diffraction（XRD）,^29Si and ^27Al nuclear magnetic resonance（NMR）.The results indicated that PESA bonds Ca^2＋ions in pore solution to prevent portlandite formation,and also combines with Ca^2＋ions on the surface of silicate minerals to prolong the control time of phase boundary reaction process,leading to the retardation of silicate mineral hydration.Meanwhile,the interlayer Ca^2＋ions in Jennite-like structure bridging PESA and C-S-H gels prevent silicate tetrahedron and aluminum tetrahedron from occupying the sites of bridging silicate tetrahedron,which causes the main existence of dimer in C-S-H structure,deceases the degree of Al^3＋substituting for Si^4＋and promotes the transformation from 4-coordination aluminum to 6-coordination aluminum.Furthermore,the-Ca^＋chelating group from reacting PESA with Ca^2＋ions combines easily with SO4^2-ions,resulting in transformation from ettringite,AFm to TAH（Third aluminum hydrate）.However,with the higher addition of PESA,it will bridge the excess PESA by Ca^2＋ions to form a new chelate with ladder-shaped double chains structure,which not only reduces the amount of PESA bonding Ca^2＋ions,but also decreases its solidifying capability for SO4^2-ions,leading to the transformation from TAH to AFm or ettringite.Meanwhile,at later hydration,the inhibition effect of PESA on cement hydration is weakened,and the transformation degree from TAH to AFm is higher than that to AFt with the addition of PESA.展开更多
his paper deals with the phase trans formation of austenite to ferrite within the critical temperature region(between Ac1 and Ac3).The results show that the volume fraction of trans formation of ferrite formed isother...his paper deals with the phase trans formation of austenite to ferrite within the critical temperature region(between Ac1 and Ac3).The results show that the volume fraction of trans formation of ferrite formed isothermally from austenite is mainly varied with the austenitizing temperature.The higher the austenitizing temperature,the more volume fraction of the ferrite formed isothermally from austenite.Besides,the phase trans formation of austenite to ferrite within the critical temperature region was checked by austenitizing isothermal time.The volume fraction of ferrite formed isothermally from austenite within the critical temperature region for different isothermal time has heen examined experimen tally.The lglg(l-fv)-1 vs lgt relation does not follow the Avrami equation strictly and consists of two straight lines.展开更多
Di-calcium magnesium silicate(Ca_(2)MgSi_(2)O_(7))doped with various concentrations(1.0 mol%,2.0 mol%,2.5 mol%,and 3.0 mol%)of dysprosium(Ⅲ)was prepared using a high-temperature technique named as solid state reactio...Di-calcium magnesium silicate(Ca_(2)MgSi_(2)O_(7))doped with various concentrations(1.0 mol%,2.0 mol%,2.5 mol%,and 3.0 mol%)of dysprosium(Ⅲ)was prepared using a high-temperature technique named as solid state reaction method.The sample with 2.5 mol%of dysprosium(Ⅲ)underwent X-ray diffraction(XRD)characterization to confirm the proper phase formation in the sample.Observed XRD pattern matched significantly with crystallographic open database(Card No.96-210-6180)with a significantly high figure of merit(0.84).Photoluminescence(PL)excitation and emission spectra were also recorded.PL excitation spectrum of Ca_(2)MgSi_(2)O_(7)doped with 2.5 mol%of dysprosium(Ⅲ)exhibited a most prominent peak at 395 nm,therefore,the emission spectra of the samples were monitored at 395 nm excitation.The emission spectra exhibited prominent peaks centered at 483 nm(blue),577 nm(yellow),and 664 nm(orange red)due to the transitions ^(4)F_(9/2)→^(6)H_(15/2),^(4)F_(9/2)→^(6)H_(13/2),and ^(4)F_(9/2)→^(6)H_(11/2),respectively.The Commission Internationale de L’Eclairage(CIE)of this emission spectra was found at(0.304,0.340)which lies in the white light region.Keeping the objective to evaluate the emitted white light for its suitability in light-emitting diode(LED)application,color rendering index(CRI)and color correlated temperature(CCT)were also calculated.Radiation life time was estimated using Judd-Ofelt analysis.展开更多
Limestone was pretreated via the mechanical activation method,and burnt lime was partially substituted by the pretreated limestone for better sinter indices and lower sintering costs.With the reduction in the size dis...Limestone was pretreated via the mechanical activation method,and burnt lime was partially substituted by the pretreated limestone for better sinter indices and lower sintering costs.With the reduction in the size distribution of the pretreated limestone,the particle morphology,the activity of the calcined limestone and the fluidity of the liquid phase during sintering are all improved.When the substitution ratio of the pretreated limestone for burnt lime is kept at 50%,the granulation performance and sinter indices in sinter pot tests are both better compared with that of the base case.Much denser interleaved texture in product sinter is formed with the reduction of sinter porosity and improvement of silico-ferrite of calcium and alumina amount.When the particle size of the pretreated limestone is maintained within the optimal range of 0–2 mm,the tumble index,yield and productivity increase by 7.2%,2.6%and 11.2%,respectively,while the solid fuel rate decreases by 8.7%.In the corresponding sinter industry production,the tumble index and output of the product sinter are comparable to those of the base case,while the coke dosage is reduced by 9.0%.Reduction index and reduction degradation index(RDI_(+3.15))are both higher than 74%.The cost of raw materials in sintering process can be greatly reduced.展开更多
The effect of(CaO+SiO_(2))mass ratio on high-Ti vanadium titanomagnetite sintering was systematically studied at the fixed basicity(CaO/SiO_(2))of 2.0.The results show that sinter matrix strength is improved with(CaO+...The effect of(CaO+SiO_(2))mass ratio on high-Ti vanadium titanomagnetite sintering was systematically studied at the fixed basicity(CaO/SiO_(2))of 2.0.The results show that sinter matrix strength is improved with(CaO+SiO_(2))mass ratio while the total iron content is reduced.Thermodynamic analysis indicates that the increase in(CaO+SiO_(2))mass ratio from 15.0 to 22.5 wt.%contributes to the formation of liquid phase,especially silico-ferrite of calcium and aluminum(SFCA).In addition,the formation of perovskite is inhibited and liquid phase fluidity is improved.The porosity of sinter matrix is reduced by 34.5%and SFCA amount is increased by 47.2%when(CaO+SiO_(2))mass ratio is increased from 15.0 to 18.0 wt.%.With the further increase in(CaO+SiO_(2))mass ratio,the structure of sinter matrix is too dense and the improved extent of SFCA amount is increasingly low.The appropriate(CaO+SiO_(2))mass ratio should be 18.0 wt.%overall.Under this condition,sinter matrix strength is greatly improved by over 13.5%compared with the base case and the total iron content can be maintained at about 49 wt.%.展开更多
Conventional intermetallics are strong but brit-tle.However,multi-principal element intermetallics,also termed as high-entropy intermetallics(HEIs)in the recent high-entropy alloy literature,are strong but malleable,s...Conventional intermetallics are strong but brit-tle.However,multi-principal element intermetallics,also termed as high-entropy intermetallics(HEIs)in the recent high-entropy alloy literature,are strong but malleable,some of which even show appreciable ductility and fracture toughness at room temperature.In this article,we provide a focused review on the recent researches on HEIs,from the fundamentals,such as the concept of HEIs,the formation rules to the structural and functional properties of HEIs.The results hitherto reported clearly show that the HEIs with distinct properties could be a promising material for future structural and functional applications.展开更多
Recently,various topics on high-entropy alloys have been reported and great amounts of excellent properties have been investigated,including high strength,great corrosion resistance,great thermal stability,good fatigu...Recently,various topics on high-entropy alloys have been reported and great amounts of excellent properties have been investigated,including high strength,great corrosion resistance,great thermal stability,good fatigue and fracture properties,etc.Among all these research activities,high-entropy alloys tend to form face-centered-cubic(FCC)or body-centeredcubic(BCC)solid solutions due to their high-entropy stabilization effect,while the hexagonal structures are rarely reported.Up to now,the reported hexagonal high-entropy alloys are mainly composed of rare-earth elements and transitional elements.Their phase transformation and magnetic properties have also aroused wide concern.This study summarizes the above results and provides the forecast to the future.展开更多
基金National Natural Science Foundation of China(U22A20191)。
文摘A series of Al-xSi-yGe filler metals(x=4–12 and y=10–40,wt%)were prepared,and the effect of Si and Ge on microstructure and melting characteristics of filler metals was studied.The thermodynamic model of Al-Si-Ge ternary alloy was established to analyze the phase formation mechanism of filler metals based on Miedema model,Tanaka model,and Toop equation.This research provided a basis for the composition optimization of filler metals and the analysis of metallurgical reaction process between filler metals and base materials.Results show that Al-Si-Ge alloy is composed of Al-Ge eutectic phase,Al-Si eutectic phase,and primary Si.Ge addition promotes the precipitation of primary Si.Ge is the main melting point depressant element of filler metals.With the increase in Ge content from 10wt%to 40wt%,the solid phase line of filler metals remains unchanged,whereas the liquidus temperature decreases from 567.65°C to 499.96°C.With the increase in Ge content of filler metal,Ge content in eutectic Si phase is increased,the endothermic peak of Al-Si eutectic reaction according to thermogravimetry curve becomes smoother,and Al-Si eutectic temperature is decreased.Ge addition can reduce the free energy of Al-Si alloy system.The lowest point of free energy is located on Al-Ge side.The eutectic Ge phase with the composition similar to pure Ge composition is the most likely to appear in the microstructure of filler metals,whereas the eutectic Si phase with the composition similar to pure Si composition is the least likely to appear.The thermodynamic calculation results are consistent with the experiment results.
基金supported by the financial support of the National Science Fund for Distinguished Young Scholars of China(No.52025014)the National Natural Science Foundation of China(Nos.52101109 and 52171090)+1 种基金the Zhejiang Provincial Natural Science Foundation of China(No.LD24E010003 and LZJWY23E090001)the Natural Science Foundation of Ningbo(Nos.2023J410).
文摘Cr_(2)AlC,a representative MAX phase,gains increasing attention for the excellent oxidation tolerance and corrosion resistance used in harsh high temperature and strong radiation environments.However,the lack of the phase formation mechanism has become the key bottleneck to the practical applications for Cr_(2)AlC synthesis with high purity at low temperatures.In this work,we fabricated the amorphous Cr-Al-C coating by a hybrid magnetron sputtering/cathodic arc deposition technique,in which the in-situ heating transmission electron microscopy(TEM)was conducted in a temperature range of 25-650℃ to address the real-time phase transformation for Cr_(2)AlC coating.The results demonstrated that increas-ing the temperature from 25 to 370℃ led to the structural transformation from amorphous Cr-Al-C to the crystalline Cr_(2)Al interphases.However,the high-purity Cr_(2)AlC MAX phase was distinctly formed at 500℃,accompanied by the diminished amorphous feature.With the further increase of temperature to 650℃,the decomposition of Cr_(2)AlC to Cr_(7)C_(3)impurities was observed.Similar phase evolution was also evidenced by the Ab-initio molecular dynamics calculations,where the bond energy of Cr-Cr,Cr-Al,and Cr-C played the key role in the formed crystalline stability during the heating process.The observa-tions not only provide fundamental insight into the phase formation mechanism for high-purity Cr_(2)AlC coatings but also offer a promising strategy to manipulate the advanced MAX phase materials with high tolerance to high-temperature oxidation and heavy ion radiations.
文摘YAG： Ce^3 ＋ phosphor particles were prepared using polyacrylamide gel method. The structure evolution of powders during annealing process was followed by X-ray diffraction determination. It is found that some intermediate phases, including θ-Al2O3, YAM and YAP, are formed when calcining polyacrylamide gel, however, the pure YAG phase can be formed directly when calcining polyacrylamide gel with α-Al2O3 as seed crystal. These facts show that the existence of α- Al2O3 seed crystal can block the formation of θ-Al2O3, YAM and YAP, and accelerate its reaction with Y2O3 to form YAG phase directly at lower temperature. The emission peak of prepared YAG ： Ce^3 ＋ phosphor is wide with maximum at 550 nm and the exitation band has two peaks, the major one is around at 460 nm, which matches the blue emission of GaN LED and is suitable for the assemble of white LED. Some fluxes can enhance the photoluminescence intensity of phosphor particles, that can be attributed both to the improvement of crystallization processes of YAG and to the stabilization of trivalence cerium ion in YAG：Ce^3 ＋.
基金Project supported by the National Basic Research Program of China(973 Program)(2014CB643703)the National Key Research and Development Program of China(2016YFB0700901)+1 种基金the National Natural Science Foundation of China(51761008,51461013)the Guangxi Natural Science Foundation(2016GXNSFDA380015,2016GXNSFGA380001)
文摘The effect of wheel speed on phase formation and magnetic properties of （Ndo.4La0.6）lsFeTzsBzs and （Ndo.4La0.6）13.4Fe79.9B6.7 ribbons prepared by melt-spinning method was investigated experimentally. Based on X-ray diffraction results, all melt-spun ribbons consist of the main phase with the tetragonal 2：14：1 type structure and the minor α-Fe phase. Magnetic measurements show the maximum magnetic energy product （（BH）max） and the remanence （Mr） increases firstly and then decreases with the increase of wheel speed, while the coercivity （Hci） increases, resulting from the variation of the average volume fraction of the ^-Fe phase and the average grain size in the melt-spun ribbons. Using Henkel plots, the interaction between the 2：14：1 phase and the ^-Fe phase in the melt-spun ribbons was analyzed and the intergranular exchange coupling is manifested. Optimal magnetic properties of Hci - 7.27 kOe, Mr - 90.94 emu/g and （BH）max -- 12.10 MGOe are achieved in the （Ndo.4La0.6）lsFeTzsBT.s ribbon with the wheel speed of 26 m/s. It indicates that magnetic properties of Nd-Fe-B melt-spun ribbons with highly abundant rare earth element La can be improved by optimizing alloy composition and preparation process.
基金the Australian Institute of Nuclear Science and Engineering(AINSE)Ltd.for providing financial assistance(Award No.P7317)to enable work on WOMBAT to be conducted.Peng Cao acknowledges the support from the International Cooperation Programs of Guangzhou City(Grant number 20190710030)Guangdong Province,China(Grant No.108A050506010).
文摘This paper characterises and evaluates Si_(3)N_(4)/Ti composites during thermal treatment using an in situ neutron diffraction technique.The composites were developed using a conventional press and sinter technique.Pure titanium(Ti)was chosen as the matrix,and different concentrations of Si_(3)N_(4)were used as the reinforcement.The effects of sintering temperature and the concentration of Si_(3)N_(4)in the Ti matrix were investigated with respect to phase constituents.The Si_(3)N_(4)mass fraction in the Ti matrix was found to be the key parameter for the reaction.Because of its instability in Ti at higher temperatures,in situ reactions between the reinforcing particles and matrix led to the formation of intermetallic compounds,such as Ti_(5)Si_(3)and possibly Ti3Si,in the composites containing higher weight fractions of Si_(3)N_(4).
文摘Boiling and fouling are taken as typical examples of new phase formation process to be analyzed and discussed in this paper. The process dynamics of nucleate boiling is analyzed and its mechanism is discussed from the view point of self-organization. Fouling, which is a more complicated phenomenon of new phase formation, involves series of underlying processes. The morphology and fractal analysis of fouling on low-energy surface and that with fouling inhibitors are studied and discussed. It is suggested that considering the process dynamics, fractal analysis and self-organization, a new avenue of research should be found.
基金the financial support by National Natural Science Foundation of China(NSFC,Grant No.51471025,No.51671020,and 51471024)
文摘Big-data analysis of phase-formation rules of high-entropy alloys（HEAs）was conducted and a phase formation rule from a dynamic view was deduced.It was indicated in literatures that cooling rate has a strong influence on the phase formation of HEAs.Higher cooling rate may promote the generation of amorphous phase,and accordingly suppress the formation of intermetallics.Meanwhile,it was also shown that cooling rate had little impact on the formation of solid-solution phase.To demonstrate this rule,a series of FeCoNi（AlSiB）xHEAs ribbons were fabricated by a melt-spinning technique,and the microstructure,mechanical,and magnetic properties were also investigated.The results show that all ribbons exhibit disordered solid-solution structure.The addition of boron changes the alloy from ductility to brittleness,but without evident change of magnetic properties.The alloy in the nominal composition of FeCoNi（AlSi）0.2has the best combination of mechanical and magnetic properties.A distinct feature of HEAs in magnetization was noticed and explained.
基金This work was supported by the National Natural Science Foundation of China (Grant No. 59671051) "863"Project.
文摘After corrosion and pitting corrosion, the wire nanometer phases are observed using a transmission electron microscope (TEM) in C+Ti dual implanted H13 steel. The property of corrosion resistance dual-implanted (C+Ti) H13 steel is studied using multi-sweep cyclic voltammetry. TEM images of the cross section of an implanted sample reveal plenty of circular nanometer structures with diameters of 10–30 nm. The phases are densely embedded in the implanted layer. The embedded structure improves the surface corrosion resistance, as can be observed with a scanning electron microscope (SEM). The phases with the shape of a tiny wire in nanometer size are formed. The nanometer phases, consisting of TiC, FeTi and FeTi2, are formed in dual implanted layer. The corrosion current peak density decreases to 1/16–1/10 that of the unimplanted H13 steel. The formation conditions of the nanometer phases and their effects are investigated. The passivation layer consists of nanometer phases. The corrosion resistance of the dual implantation can be further enhanced with an increase in ion dose.
基金financially supported by the following sources:Guangdong Basic and Applied Basic Research Foundation(No.2023B1515120045)Yangjiang City Key Industry Talent Revitalization Plan Project for Alloy Materials and Hardware Scissors(No.RCZX202302)+7 种基金GDAS'Project of Science and Technology Development(Nos.2022GDASZH-2022010108,2022GD ASZH-2022010107 and 2024GD ASZH-2024010102)GDAS'Young Talent Project(No.2024GDASQNRC-0314)Guangzhou Basic and Applied Basic Research Foundation(No.2023A04J1628)the National Key R&D Program of China(No.2022YFB4600700)National Natural Science Foundation of China(No.52371110)Guangdong Basic and Applied Basic Research Foundation(No.2023A1515011510)Shenzhen Science and Technology Program(Nos.JCYJ20220530115011026 and JCYJ20230807093410021)Shanxi Province Key R&D Project(No.202302050201011)
文摘A novel approach for fabricating multi-principal element alloys with adjustable phase configurations and mechanical properties was developed using laser-aided additive manufacturing(LAAM),combining FCC-structured(face-centered cubic)CoCrNi and BCC-structured(body-centered cubic)CoCrNiAl0.6TiFe feedstocks.During fabrication,CoCrNi powders and CoCrNiAl0.6TiFe powders were simultaneously fed into the melt pool at individually adjustable rates,allowing for controlled phase transitions.The resulting phase evolution demonstrated a gradual transition from a single FCC structure CoCrNi(A10.6TiFe)x(x=0,0.1,0.2,0.3)to a dual FCCB2 structure CoCrNi(Al0.6TiFe)x(x=0.4,0.5)as the proportion of BCC-structured powders increased.The B2 phase,enriched in Ti and Al due to their larger atomic radii and negative segregation enthalpy,precipitated around the FCC matrix,with volume fractions of 0.5%and 5.7%for CoCrNi(A10.6TiFe)0.4 and CoCrNi(A10.6TiFe)0.5,respectively.This phase transition resulted in significant mechanical enhancements.Yield and ultimate tensile strengths increased from 486.0 and 781.2 MPa(CoCrNi)to 887.2 and 1165.2 MPa(CoCrNi(A10.6TiFe)0.5).Dislocation-mediated hardening prevailed in single-phase FCC alloys,exhibiting a characteristic dislocation density of 2.5×10^(15)m^(-2)for CoCrNi(A10.6TiFe)0.3 alloy.Once the B2 phase precipitated,precipitation strengthening became dominant,as observed in transmission electron microscopy(TEM),where dislocations accumulated around B2 precipitates.This study presents an innovative alloy fabrication strategy that enables precise tuning of FCC-BCC dualphase structures,facilitating the direct fabrication of components with spatially customized properties.These findings provide valuable insights for developing multiprincipal element alloys with heterogeneous microstructures for advanced engineering applications.
基金financially supported by the Open Fund (grant No. PLC 20180404) of State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation, Chengdu University of Technology
文摘Shale gas has currently attracted much attention during oil and gas exploration and development. Fractures in shale have an important influence on the enrichment and preservation of shale gas. This work studied the developmental period and formation mechanism of tectonic fractures in the Longmaxi Formation shale in the Dingshan area of southeastern Sichuan Basin based on extensive observations of outcrops and cores, rock acoustic emission(Kaiser) experiments, homogenization temperature of fracture fill inclusions, apatite fission track, thermal burial history. The research shows that the fracture types of the Longmaxi Formation include tectonic fractures, diagenetic fractures and horizontal slip fractures. The main types are tectonic high-angle shear and horizontal slip fractures, with small openings, large spacing, low densities, and high degrees of filling. Six dominant directions of the fractures after correction by plane included NWW, nearly SN, NNW, NEE, nearly EW and NW. The analysis of field fracture stage and fracture system of the borehole suggests that the fractures in the Longmaxi Formation could be paired with two sets of plane X-shaped conjugate shear fractures, i.e., profile X-shaped conjugate shear fractures and extension fractures. The combination of qualitative geological analysis and quantitative experimental testing techniques indicates that the tectonic fractures in the Longmaxi Formation have undergone three periods of tectonic movement, namely mid-late Yanshanian movement(82–71.1 Ma), late Yanshanian and middle Himalaya movements(71.1–22.3 Ma), and the late Himalayan movement(22.3–0 Ma). The middle-late period of the Yanshanian movement and end of the Yanshanian movement-middle period of the Himalayan movement were the main fractureforming periods. The fractures were mostly filled with minerals, such as calcite and siliceous. The homogenization temperature of fracture fill inclusions was high, and the paleo-stress value was large; the tectonic movement from the late to present period was mainly a slight transformation and superposition of existing fractures and tectonic systems. Based on the principle of tectonic analysis and theory of geomechanics, we clarified the mechanism of the fractures in the Longmaxi Formation, and established the genetic model of the Longmaxi Formation. The research on the qualitative and quantitative techniques of the fracture-phase study could be effectively used to analyze the causes of the marine shale gas fractures in the Sichuan Basin. The research findings and results provide important references and technical support for further exploration and development of marine shale gas in South China.
文摘Elemental powders of Cu and Fe were ball milled for various time durations up to 100 h. The various stages of forced alloying by ball milling, leading to instability of elemental crystalline phases and formation of quasicrystalline phases were monitored using X-ray diffraction. Diffusion of Fe into the Cu matrix is proposed as the cause which triggers the instability of crystalline phases and leads to the formation of quasicrystalline phases after 10 h of milling. Milling for 100 h resulted in two different quasicrystalline phases with different lattice constants. Role of the nanocrystalline microstructure as an important criterion for the destabilisation of crystalline phases is explained. It is suggested that the formation of nanocrystalline microstructure and their subsequent transformation into quasicrystalline phases may be associated with a continuous increase in the disclination content of the system, which had formed as a result of continued milling and mechanical deformation.
基金supported by the National Natural Science Foundation of China(Nos.51971021 and 11775017)the National Magnetic Confinement Fusion Program of China(No.2019YFE03130002).
文摘A novel low-activation Ti_(1.5)ZrV_(0.5)Ta_(0.5)refractory high-entropy alloy(RHEA)was designed as a potential candidate for nuclear reactor application.At room temperature,it had an elongation of 8.4%and a yield strength of 1096 MPa.The phase evolution of this alloy and its effect on properties was investigated.At 400℃,the solid solution bcc 1 transformed into the fcc phase and bcc 2 phase,and theωphase andαphase also appeared.At 600℃,theωphase andαphase disappeared,and the microstructure of the alloy was composed of the fcc phase and bcc 2 phase.When the temperature was up to 1200℃,the fcc phase and bcc 2 phase re-transformed into solid solution bcc 1 phase.The precipitation ofωphase andαphase caused a sharp increase in strength and a decrease in plasticity.Meanwhile,the appearance of the fcc phase led to a simultaneous decrease in strength and ductility,due to larger stress concentrations at the fcc/bcc interface.Besides,the formation mechanism of each phase in the alloy was discussed in detail.
文摘For the first time, DySrA104 of K2NiF4-type structure was synthesized. The parameters of DySrA104 ele- mentary unit cell are determined as follows： a = 0.368 （4） nm, c = 1.229 （2） nm, V = 0.166 （4） nm3. The research of the complex aluminates ZnSrA104 （Ln = Nd, Gd, Dy） solid-state process demonstrated the change of the formation mecha- nism among LnSrA104 （Ln = Nd, Gd, Dy） series from DySrA104 oxide. The performed analysis provided a possibility to realize why chemists couldn＇t get DySrA104 for a long period of time.
基金Funded by the Major State Basic Research Development Program of China(973 Program)(No.2015CB655101)Hubei Key Laboratory of Roadway Bridge and Structure Engineering(Wuhan University of Technology)(No.DQZDJJ201504)+2 种基金State Key Laboratory of High Performance Civil Engineering Materials(No.2015CEM006)Natural Science Foundation of Hebei Province(No.E2016209283)Science and Technology Program of Hebei Province(No.16273706D)
文摘The influence of polyepoxysuccinic acid（PESA）on the solid phase products in hydrated Portland cement pastes was investigated by isothermal calorimetry,X-ray diffraction（XRD）,^29Si and ^27Al nuclear magnetic resonance（NMR）.The results indicated that PESA bonds Ca^2＋ions in pore solution to prevent portlandite formation,and also combines with Ca^2＋ions on the surface of silicate minerals to prolong the control time of phase boundary reaction process,leading to the retardation of silicate mineral hydration.Meanwhile,the interlayer Ca^2＋ions in Jennite-like structure bridging PESA and C-S-H gels prevent silicate tetrahedron and aluminum tetrahedron from occupying the sites of bridging silicate tetrahedron,which causes the main existence of dimer in C-S-H structure,deceases the degree of Al^3＋substituting for Si^4＋and promotes the transformation from 4-coordination aluminum to 6-coordination aluminum.Furthermore,the-Ca^＋chelating group from reacting PESA with Ca^2＋ions combines easily with SO4^2-ions,resulting in transformation from ettringite,AFm to TAH（Third aluminum hydrate）.However,with the higher addition of PESA,it will bridge the excess PESA by Ca^2＋ions to form a new chelate with ladder-shaped double chains structure,which not only reduces the amount of PESA bonding Ca^2＋ions,but also decreases its solidifying capability for SO4^2-ions,leading to the transformation from TAH to AFm or ettringite.Meanwhile,at later hydration,the inhibition effect of PESA on cement hydration is weakened,and the transformation degree from TAH to AFm is higher than that to AFt with the addition of PESA.
文摘his paper deals with the phase trans formation of austenite to ferrite within the critical temperature region(between Ac1 and Ac3).The results show that the volume fraction of trans formation of ferrite formed isothermally from austenite is mainly varied with the austenitizing temperature.The higher the austenitizing temperature,the more volume fraction of the ferrite formed isothermally from austenite.Besides,the phase trans formation of austenite to ferrite within the critical temperature region was checked by austenitizing isothermal time.The volume fraction of ferrite formed isothermally from austenite within the critical temperature region for different isothermal time has heen examined experimen tally.The lglg(l-fv)-1 vs lgt relation does not follow the Avrami equation strictly and consists of two straight lines.
文摘Di-calcium magnesium silicate(Ca_(2)MgSi_(2)O_(7))doped with various concentrations(1.0 mol%,2.0 mol%,2.5 mol%,and 3.0 mol%)of dysprosium(Ⅲ)was prepared using a high-temperature technique named as solid state reaction method.The sample with 2.5 mol%of dysprosium(Ⅲ)underwent X-ray diffraction(XRD)characterization to confirm the proper phase formation in the sample.Observed XRD pattern matched significantly with crystallographic open database(Card No.96-210-6180)with a significantly high figure of merit(0.84).Photoluminescence(PL)excitation and emission spectra were also recorded.PL excitation spectrum of Ca_(2)MgSi_(2)O_(7)doped with 2.5 mol%of dysprosium(Ⅲ)exhibited a most prominent peak at 395 nm,therefore,the emission spectra of the samples were monitored at 395 nm excitation.The emission spectra exhibited prominent peaks centered at 483 nm(blue),577 nm(yellow),and 664 nm(orange red)due to the transitions ^(4)F_(9/2)→^(6)H_(15/2),^(4)F_(9/2)→^(6)H_(13/2),and ^(4)F_(9/2)→^(6)H_(11/2),respectively.The Commission Internationale de L’Eclairage(CIE)of this emission spectra was found at(0.304,0.340)which lies in the white light region.Keeping the objective to evaluate the emitted white light for its suitability in light-emitting diode(LED)application,color rendering index(CRI)and color correlated temperature(CCT)were also calculated.Radiation life time was estimated using Judd-Ofelt analysis.
基金supported by Natural Science Foundation of Chongqing(No.CSTB2023NSCQ-BHX0166)Postdoctoral Science Foundation of China(No.2024T171095)Fundamental Research Funds for the Central Universities(No.2024CDJXY003).
文摘Limestone was pretreated via the mechanical activation method,and burnt lime was partially substituted by the pretreated limestone for better sinter indices and lower sintering costs.With the reduction in the size distribution of the pretreated limestone,the particle morphology,the activity of the calcined limestone and the fluidity of the liquid phase during sintering are all improved.When the substitution ratio of the pretreated limestone for burnt lime is kept at 50%,the granulation performance and sinter indices in sinter pot tests are both better compared with that of the base case.Much denser interleaved texture in product sinter is formed with the reduction of sinter porosity and improvement of silico-ferrite of calcium and alumina amount.When the particle size of the pretreated limestone is maintained within the optimal range of 0–2 mm,the tumble index,yield and productivity increase by 7.2%,2.6%and 11.2%,respectively,while the solid fuel rate decreases by 8.7%.In the corresponding sinter industry production,the tumble index and output of the product sinter are comparable to those of the base case,while the coke dosage is reduced by 9.0%.Reduction index and reduction degradation index(RDI_(+3.15))are both higher than 74%.The cost of raw materials in sintering process can be greatly reduced.
基金supported by National Natural Science Foundation of China(No.52304344)Postdoctoral Science Foundation of China(No.2024T171095)Cooperation Project of Pangang Group.Author information。
文摘The effect of(CaO+SiO_(2))mass ratio on high-Ti vanadium titanomagnetite sintering was systematically studied at the fixed basicity(CaO/SiO_(2))of 2.0.The results show that sinter matrix strength is improved with(CaO+SiO_(2))mass ratio while the total iron content is reduced.Thermodynamic analysis indicates that the increase in(CaO+SiO_(2))mass ratio from 15.0 to 22.5 wt.%contributes to the formation of liquid phase,especially silico-ferrite of calcium and aluminum(SFCA).In addition,the formation of perovskite is inhibited and liquid phase fluidity is improved.The porosity of sinter matrix is reduced by 34.5%and SFCA amount is increased by 47.2%when(CaO+SiO_(2))mass ratio is increased from 15.0 to 18.0 wt.%.With the further increase in(CaO+SiO_(2))mass ratio,the structure of sinter matrix is too dense and the improved extent of SFCA amount is increasingly low.The appropriate(CaO+SiO_(2))mass ratio should be 18.0 wt.%overall.Under this condition,sinter matrix strength is greatly improved by over 13.5%compared with the base case and the total iron content can be maintained at about 49 wt.%.
基金financially supported by the General Research Fund (GRF) from Research Grant Council,the Hong Kong Government (Nos.CityU11213118 and CityU11200719)the fund from City University of Hong Kong (No.7005438)
文摘Conventional intermetallics are strong but brit-tle.However,multi-principal element intermetallics,also termed as high-entropy intermetallics(HEIs)in the recent high-entropy alloy literature,are strong but malleable,some of which even show appreciable ductility and fracture toughness at room temperature.In this article,we provide a focused review on the recent researches on HEIs,from the fundamentals,such as the concept of HEIs,the formation rules to the structural and functional properties of HEIs.The results hitherto reported clearly show that the HEIs with distinct properties could be a promising material for future structural and functional applications.
基金financial support from the National Natural Science Foundation of China (No 51671020)Fundamental Research Funds for the Central Universities (No. FRF-MP-19-013)。
文摘Recently,various topics on high-entropy alloys have been reported and great amounts of excellent properties have been investigated,including high strength,great corrosion resistance,great thermal stability,good fatigue and fracture properties,etc.Among all these research activities,high-entropy alloys tend to form face-centered-cubic(FCC)or body-centeredcubic(BCC)solid solutions due to their high-entropy stabilization effect,while the hexagonal structures are rarely reported.Up to now,the reported hexagonal high-entropy alloys are mainly composed of rare-earth elements and transitional elements.Their phase transformation and magnetic properties have also aroused wide concern.This study summarizes the above results and provides the forecast to the future.
