(NbZrHfTi)C high-entropy ceramics,as an emerging class of ultra-high-temperature materials,have garnered significant interest due to their unique multi-principal-element crystal structure and exceptional hightemperatu...(NbZrHfTi)C high-entropy ceramics,as an emerging class of ultra-high-temperature materials,have garnered significant interest due to their unique multi-principal-element crystal structure and exceptional hightemperature properties.This study systematically investigates the mechanical properties of(NbZrHfTi)C high-entropy ceramics by employing first-principles density functional theory,combined with the Debye-Grüneisen model,to explore the variations in their thermophysical properties with temperature(0–2000 K)and pressure(0–30 GPa).Thermodynamically,the calculated mixing enthalpy and Gibbs free energy confirm the feasibility of forming a stable single-phase solid solution in(NbZrHfTi)C.The calculated results of the elastic stiffness constant indicate that the material meets the mechanical stability criteria of the cubic crystal system,further confirming the structural stability.Through evaluation of key mechanical parameters—bulk modulus,shear modulus,Young’s modulus,and Poisson’s ratio—we provide comprehensive insight into the macro-mechanical behaviour of the material and its correlation with the underlying microstructure.Notably,compared to traditional binary carbides and their average properties,(NbZrHfTi)C exhibits higher Vickers hardness(Approximately 28.5 GPa)and fracture toughness(Approximately 3.4 MPa⋅m^(1/2)),which can be primarily attributed to the lattice distortion and solid-solution strengthening mechanism.The study also utilizes the quasi-harmonic approximation method to predict the material’s thermophysical properties,including Debye temperature(initial value around 563 K),thermal expansion coefficient(approximately 8.9×10^(−6) K−1 at 2000 K),and other key parameters such as heat capacity at constant volume.The results show that within the studied pressure and temperature ranges,(NbZrHfTi)C consistently maintains a stable phase structure and good thermomechanical properties.The thermal expansion coefficient increasing with temperature,while heat capacity approaches the Dulong-Petit limit at elevated temperatures.These findings underscore the potential of(NbZrHfTi)C applications in ultra-high temperature thermal protection systems,cutting tool coatings,and nuclear structural materials.展开更多
Oxygen carriers play a fundamental role in chemical looping combustion(CLC).Iron-based carriers have been extensively investigated owing to their abundance and environmentally friendly.However,the reactivity and separ...Oxygen carriers play a fundamental role in chemical looping combustion(CLC).Iron-based carriers have been extensively investigated owing to their abundance and environmentally friendly.However,the reactivity and separability of iron-based carriers require further enhancement.This study investigates the effect of the concentration of Mn doping on reactivity,elastic properties and magnetic properties based on density functional theory(DFT)calculations.Theoretical results demonstrate that Mn doping effectively enhances reactivity by reducing the oxygen vacancy formation energy(E_(vac))from 2.33 to 0.87 eV.However,Mn doping introduces HV/EV Ms lattice distortions that deteriorate elastic properties,thereby reducing wear resistance,as evidenced by a 54.54%decrease in the hardness-to-Young's modulus ratio(H_(v)/E_(v))forα-Fe_(2)O_(3)and an 83.33%reduction for Fe_(3)O_(4).Furthermore,Mn doping also modifies magnetic properties.The maximum of saturation magnetization(M_(s))of Fe_(3)O_(4)reaches 121.02 emu/g at 33.33%Mn doping concentration.Finally,systematic evaluation identifies 33.33%as the optimal Mn doping concentration,achieving a balance in enhanced reactivity,superior magnetic performance,and retained elastic stability.展开更多
SiO_(2)–CaO–Al_(2)O_(3)ternary inclusions are among the most common complex oxide inclusions in steel.Nevertheless,the chemical and physical properties of these composite inclusions,particularly with detailed compos...SiO_(2)–CaO–Al_(2)O_(3)ternary inclusions are among the most common complex oxide inclusions in steel.Nevertheless,the chemical and physical properties of these composite inclusions,particularly with detailed composition changes,have not been sufficiently investigated.In this study,first-principles density functional theory calculations were used to determine the electronic,mechanical,and thermodynamic properties of two stable phases in the SiO_(2)–CaO–Al_(2)O_(3)ternary inclusion system:anorthite(CaAl_(2)Si_(2)O_(8))and gehlenite(Ca_(2)Al_(2)SiO_(7)).Based on the electronic density of states analysis and band structure calculations,oxygen atoms play important roles in the electron reactivity of both phases.Young’s modulus and Poisson’s ratios were calculated and compared with those of the SiO_(2)–CaO inclusions.The Young’s moduli of CaAl_(2)Si_(2)O_(8)(101.32 GPa)and Ca_(2)Al_(2)SiO_(7)(131.43 GPa)were close to the maximum and minimum Young’s moduli of the binary oxide inclusions,respectively.With increasing temperature,the Young’s moduli of CaAl_(2)Si_(2)O_(8)and Ca_(2)Al_(2)SiO_(7)showed slight increasing and decreasing trends,respectively,whereas the Poisson’s ratio decreased.Furthermore,the thermodynamic properties,particularly temperature-related thermal expansion coefficients,were also deeply investigated.The thermal expansion coefficients of both CaAl_(2)Si_(2)O_(8)and Ca_(2)Al_(2)SiO_(7)increased rapidly with increasing temperature in the low-temperature regime above 300K.As the temperature increased,the increasing trend slowed.When the temperature reached 2000 K,the thermal expansion coefficients of CaAl_(2)Si_(2)O_(8)and Ca_(2)Al_(2)SiO_(7)respectively were 12×10^(−6)and 8.5×10^(−6)K^(−1).These findings enhance the understanding of the physical nature of ternary inclusions in steels and provide a scientific foundation for analyzing their effects on steel performance using a more comprehensive inclusion database,thereby contributing to inclusion engineering in the development of materials with superior mechanical integrity.展开更多
This study investigates the properties of high-purity starches extracted from Polygonum multiflorum(PMS)and Smilax glabra(SGS).The starches were characterized by scanning electron microscopy,Fouriertransform infrared ...This study investigates the properties of high-purity starches extracted from Polygonum multiflorum(PMS)and Smilax glabra(SGS).The starches were characterized by scanning electron microscopy,Fouriertransform infrared spectroscopy,X-ray diffraction,high-performance anion-exchange chromatography,and differential scanning calorimetry.Significant differences were observed in their morphological,physicochemical,and functional properties.PMS had a smaller particle size(13.68 μm),irregular polygonal shape,A-type,lower water absorption(62.67 %),and higher oil absorption(51.17 %).In contrast,SGS exhibited larger particles(31.75 μm),a nearly spherical shape,B-type,higher crystallinity(50.66 %),and greater amylose content(21.54 %),with superior thermal stability,shear resistance,and gelatinization enthalpy.SGS also contained higher resistant starch(83.28 %) and longer average chain length(20.58 %),but showed lower solubility,swelling power,light transmittance,and freeze-thaw stability.The physicochemical properties differences in crystal pattern and particle morphology between PMS and SGS lead to distinct behaviors during in vitro digestion and fermentation.These findings highlight the potential of medicinal plant starches in functional ingredients and industrial processes.展开更多
The effect of element Ti on the microstructures and mechanical properties of as-cast and annealed NbTaMoWTi,(x=0,1,1.5,2)refractory high-entropy alloys(RHEAs)was investigated.Results show that after Ti addition,the as...The effect of element Ti on the microstructures and mechanical properties of as-cast and annealed NbTaMoWTi,(x=0,1,1.5,2)refractory high-entropy alloys(RHEAs)was investigated.Results show that after Ti addition,the as-cast alloys maintain their original single body-centered cubic(bcc)structure.As for the mechanical properties,compared with those without Ti addition,the strength and ductility of NbTaMoWTi,alloys increase by 93%and 215%,respectively.Furthermore,the NbTaMoWTi alloys exhibit outstanding thermal stability.After annealing at 1400 C,they still maintain the single bcc structure,and their mechanical properties are even slightly improved.However,annealing leads to a significant deterioration in the mechanical properties of high-Ti-content alloys(NbTaMoWTil and NbTaMoWTi2),owing to the formation of Ti-rich acicular phases.展开更多
The strength and damping properties of Co-Ni-Cr-Mo-based alloys with 0.5wt%Nb addition after various plastic deformation and heat treatment processes were investigated.Through Vickers hardness tests,free resonance You...The strength and damping properties of Co-Ni-Cr-Mo-based alloys with 0.5wt%Nb addition after various plastic deformation and heat treatment processes were investigated.Through Vickers hardness tests,free resonance Young's modulus measurements,and microstructure analysis,the effects of dislocation density,vacancy formation,and recrystallization on the alloy performance were clarified.Results indicate that increasing the rolling reduction enhances damping property due to higher dislocation density,whereas aging below the recrystallization temperature reduces damping property via dislocation pinning by the Suzuki effect.Recrystallization heat treatment restores the original structure and damping level.This alloy possesses tensile strength of approximately 1500 MPa and logarithmic decrement valueδ^(-1) in the range of 2×10^(-4)–3×10^(-4),demonstrating superior mechanical properties compared with the Ti-based alloys,which makes it an excellent candidate material for ultrasonic tools and medical applications.展开更多
Three zinc(Ⅱ),nickel(Ⅱ),and cadmium(Ⅱ)complexes,namely[Zn(μ-Htpta)(py)_(2)]n(1),[Ni(H_(2)biim)2(H_(2)O)2][Ni(tpta)(H_(2)biim)2(H_(2)O)]2·3H_(2)O(2),and[Cd_(3)(μ4-tpta)2(μ-dpe)_(3)]_(n)(3),have been construc...Three zinc(Ⅱ),nickel(Ⅱ),and cadmium(Ⅱ)complexes,namely[Zn(μ-Htpta)(py)_(2)]n(1),[Ni(H_(2)biim)2(H_(2)O)2][Ni(tpta)(H_(2)biim)2(H_(2)O)]2·3H_(2)O(2),and[Cd_(3)(μ4-tpta)2(μ-dpe)_(3)]_(n)(3),have been constructed hydrothermally at 160℃ using H_(3)tpta([1,1':3',1″-terphenyl]-4,4',5'-tricarboxylic acid),py(pyridine),H_(2)biim(2,2'-biimidazole),dpe(1,2-di(4-pyridyl)ethylene),and zinc,nickel and cadmium chlorides,resulting in the formation of stable crystalline solids which were subsequently analyzed using infrared spectroscopy,element analysis,thermogravimetric analysis,as well as structural analyses conducted via single-crystal X-ray diffraction.The findings from these single-crystal Xray diffraction studies indicate that complexes 1-3 form crystals within the monoclinic system P2_(1)/c space group(1)or triclinic system P1 space group(2 and 3),and possess 1D,0D,and 3D structures,respectively.Complex 1 demonstrated substantial catalytic efficiency and excellent reusability as a heterogeneous catalyst in the reaction of Knoevenagel condensation under ambient temperature conditions.In addition,complex 1 also showcased notable anti-wear performance when used in polyalphaolefin synthetic lubricants.CCDC:2449810,1;2449811,2;2449812,3.展开更多
Dissimilar AZ31B magnesium alloy and DC56D steel were welded via AA1060 aluminum alloy by magnetic pulse welding.The effects of primary and secondary welding processes on the welded interface were comparatively invest...Dissimilar AZ31B magnesium alloy and DC56D steel were welded via AA1060 aluminum alloy by magnetic pulse welding.The effects of primary and secondary welding processes on the welded interface were comparatively investigated.Macroscopic morphology,microstructure,and interfacial structure of the joints were analyzed using scanning electron microscope,energy dispersive spectrometer,and X-ray diffractometer(XRD).The results show that magnetic pulse welding of dissimilar Mg/Fe metals is achieved using an Al interlayer,which acts as a bridge for deformation and diffusion.Specifically,the AZ31B/AA1060 interface exhibits a typical wavy morphology,and a transition zone exists at the joint interface,which may result in an extremely complex microstructure.The microstructure of this transition zone differs from that of AZ31B magnesium and 1060 Al alloys,and it is identified as brittle intermetallic compounds(IMCs)Al_(3)Mg_(2) and Al_(12)Mg_(17).The transition zone is mainly distributed on the Al side,with the maximum thickness of Al-side transition layer reaching approximately 13.53μm.Incomplete melting layers with varying thicknesses are observed at the primary weld interface,while micron-sized hole defects appear in the transition zone of the secondary weld interface.The AA1060/DC56D interface is mainly straight,with only a small number of discontinuous transition zones distributed intermittently along the interface.These transition zones are characterized by the presence of the brittle IMC FeAl_(3),with a maximum thickness of about 4μm.展开更多
To maintain soil quality under long-term saline water irrigation,the influence of manure on soil physical properties was examined.Long-term saline irrigation has been conducted from 2015 to 2024 at the Nanpi Eco-Agric...To maintain soil quality under long-term saline water irrigation,the influence of manure on soil physical properties was examined.Long-term saline irrigation has been conducted from 2015 to 2024 at the Nanpi Eco-Agricultural Experimental Station of Chinese Academy Sciences in the Low Plain of the North China Plain,comprising four irrigation treatments:irrigation once at the jointing stage for winter wheat with irrigation water containing salt at fresh water,3,4 and 5 g·L^(–1),and maize irrigation at sowing using fresh water.Manure application was conducted under all irrigation treatments,with treatments without manure application used as controls.The results showed that under long-term irrigation with saline water,the application of manure increased the soil organic matter content,exchangeable potassium,available phosphorus,and total nitrogen content in the 0–20 cm soil layer by 46.8%,117.0%,75.7%,and 45.5%,respectively,compared to treatments without manure application.The application of manure reduced soil bulk density.It also increased the proportion of water-stable aggregates and the abundance of bacteria,fungi,and actinomycetes in the tillage soil layer compared to the controls.Because of the salt contained in the manure,the application of manure had dual effects on soil salt content.During the winter wheat season,manure application increased soil salt content.The salt content was significantly reduced during the summer maize season,owing to the strong salt-leaching effects under manure application,resulting in a smaller difference in salt content between the manure and non-manure treatments.During the summer rainfall season,improvements in soil structure under manure application increased the soil desalination rate for the 1 m top soil layer.The desalination rate for 0–40 cm and 40–100 cm was averagely by 39.1%and 18.9%higher,respectively,under manure application as compared with that under the nomanure treatments.The yield of winter wheat under manure application was 0.12%lower than that of the control,owing to the higher salt content during the winter wheat season.In contrast,the yield of summer maize improved by 3.9%under manure application,owing to the increased soil nutrient content and effective salt leaching.The results of this study indicated that manure application helped maintain the soil physical structure,which is important for the long-term use of saline water.In practice,using manure with a low salt content is suggested to reduce the adverse effects of saline water irrigation on soil properties and achieve sustainable saline water use.展开更多
The effects of channel segregation on the macro-and micro-scale chemical composition,microstructure,hardness,and tensile deformation behavior of Ti45Nb wires were investigated.The results show that wires with severe c...The effects of channel segregation on the macro-and micro-scale chemical composition,microstructure,hardness,and tensile deformation behavior of Ti45Nb wires were investigated.The results show that wires with severe channel segregation exhibit a macroscopic chemical composition identical to those without segregation,and 3D X-ray imaging result also reveals no abnormalities.After annealing,both types of wires exhibit an equiaxed single-phase microstructure with comparable grain sizes,suggesting that channel segregation has negligible influence on the macroscopic composition and grain size.Metallographic examination reveals that channel segregation manifests as spot-like features in the transverse section and band-like structures in the longitudinal section.EDS analysis identifies these regions as Ti-enriched segregations,with a Ti content higher than that of the surrounding matrix by approximately 4.42wt%.Compared to segregation-free wires,those containing extensive channel segregation demonstrate a 15.5%increase in ultimate tensile strength and a 12.3%increase in yield strength,but suffer a reduction in elongation and reduction of area by 19.8%and 18.9%,respectively.Furthermore,the mechanical properties of wires with segregation show significant fluctuations.Fractographic analysis reveals a larger fracture surface area in segregated wires.Severe dislocation pile-ups occur at the interfaces of these segregated regions,initiating microcrack nucleation.This promotes rapid crack propagation of the Ti45Nb wire,leading to a significant decrease in plasticity and reduction of area.展开更多
Polyurea(PUA)is widely valued in protective coatings and structural reinforcement because of its impressive mechanical strength and resistance to corrosion.Its high flammability,together with the poor dispersion that ...Polyurea(PUA)is widely valued in protective coatings and structural reinforcement because of its impressive mechanical strength and resistance to corrosion.Its high flammability,together with the poor dispersion that often comes with simply blending in flame retardants,continues to limit its use in demanding environments.To overcome these issues,this study introduces a different approach.We grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO)onto the surface of a metal-organic framework(MOF)and then partially amino-functionalized the DOPO layer,ultimately creating an amino-modified DOPO-MOF hybrid.The introduced amino groups can directly react with the isocyanate(-NCO)groups in the PUA matrix,allowing the flame-retardant component to be integrated via reactive integration rather than physical blending.This approach helps avoid the interfacial defects and the mechanical weakening typically observed in conventional blending.With 5 wt% ZIF-67@DOPO-NH2 added to the PUA system,the composite successfully reached a UL-94 V-0 classification and showed a notable increase in limiting oxygen index(LOI),from19.2% to 23.8%.The peak heat release rate and total heat release dropped by 36.3% and 38.7%,respectively.Meanwhile,the tensile strength decreased from 25.74 to 22.52 MPa,while the elongation at break remained above 300%,indicating that the material maintained excellent toughness.展开更多
In the casting process of 1060 industrial pure aluminum,the inclusions in the aluminum melt significantly affect the product quality.In this study,the influence of refining temperature and the composition of salt flux...In the casting process of 1060 industrial pure aluminum,the inclusions in the aluminum melt significantly affect the product quality.In this study,the influence of refining temperature and the composition of salt fluxes on the purification effect and mechanical properties of aluminum melt was investigated.The results indicate that lower refining temperatures and modified salt fluxes can effectively enhance the cleanliness of the aluminum melt.As the refining temperature increases,the large inclusions gradually increase.The addition of16wt.%Na_(3)AlF_(6) can dissolve and break up Al_2O_(3) inclusions,facilitating the separation of the aluminum melt and aluminum slag.The addition of 16wt.%Na3AlF6 and 2wt.%CaCO_(3) to the basic salt fluxes enables gas refinement,thereby further improving the cleanliness of the aluminum melt.Under the refining condition of 37wt.%NaCl-47wt.%KCl--16wt.%Na3AIF3-2wt.%CaCO_(3) at 740℃,better cleanliness and mechanical properties were obtained.The cleanliness and yield strength are approximately 99.99928%and 71.46 MPa,respectively.This work can offer valuable reference and theoretical insights for future research.展开更多
To comprehensively explore the impact of binder content on the mechanical properties of the Polymer bonded explosive(PBX)substitute material(Polymer-bonded Analogue Explosive(PAE)—it is renowned for its outstanding h...To comprehensively explore the impact of binder content on the mechanical properties of the Polymer bonded explosive(PBX)substitute material(Polymer-bonded Analogue Explosive(PAE)—it is renowned for its outstanding high-temperature resistance,exceptional mechanical properties,excellent chemical stability,and superior electrical insulation),a series of experiments are meticulously carried out.The dynamic and static mechanical properties,along with the microstructure of PAE,are precisely measured through the Split Hopkinson Pressure Bar(SHPB)test,static compression tests,and Scanning Electron Microscopy(SEM).The dynamic performance test outcomes clearly indicate that both the binder content(2%,4%,6%)and temperature(25℃,45℃,70℃)exert a substantial influence on the dynamic mechanical properties of PAE.Specifically,as the binder content increases,the elasticmodulus increases,demonstrating higher stiffness,and the longer failure duration represents a prolonged fracture process rather than an improved deformation strain to failure.This means the strength-related stiffness rises with binder content,but the overall ductility does not increase.Notably,PAE with 2%the Ethylene-Vinyl Acetate Copolymer(EVA)—it bonds well with a variety ofmaterials,such asmetal,wood,and plastic—exhibits distinct plastic deformation behavior,while PAE samples with 4%and 6%EVA display evident brittle fracture characteristics.Additionally,the mechanical properties of PAE are highly sensitive to temperature variations.Among the tested temperatures,PAE showcases the most favorable performance at 45℃.The static performance test results reveal that an increment in binder content effectively helps to reduce the temperature sensitivity of temperature(-40℃,25℃,50℃,70℃)on PAE and enhance its static mechanical properties.The maximum compressive strength gradually diminishes as the temperature rises.However,it should be noted that an excessively high binder content will undermine the mechanical properties of PAE.With the increase in binder content,the compressive modulus demonstrates relatively stable changes under both lowtemperature and high-temperature conditions.The SEM analysis results demonstrate that,aside fromthe initial defects inherent in the material preparation process,the components of PAE are firmly combined.Throughout the tests,no new pores or microcracks emerge,which strongly indicates that the mechanical properties of PAE remain stable.展开更多
The laser-clad Fe45 alloy coating inherently comprises multiple crystalline phases,resulting in a heterogeneous microstructural distribution that influences its performance.In this study,the rare earth yttria(Y_(2)O_(...The laser-clad Fe45 alloy coating inherently comprises multiple crystalline phases,resulting in a heterogeneous microstructural distribution that influences its performance.In this study,the rare earth yttria(Y_(2)O_(3))was employed to modify laser-clad Fe45 alloy coatings,and the effects of Y_(2)O_(3) addition on their microstructure,microhardness,and tribological properties were investigated.As the Y_(2)O_(3) content increases from 0%to 0.3wt.%,the dominant microstructure transforms from columnar crystals to fine cellular and equiaxed crystals.The modified coating with 0.3wt.%Y_(2)O_(3) achieves a surface hardness of 568 HV_(0.3)and a wear volume of 1,735.41 um~3,representing a 14.06%increase in hardness and a 51.16%reduction in wear volume compared to the undoped coating.Further increasing the Y_(2)O_(3) content from 0.3wt.%to 0.9wt.%gradually leads to the emergence of a coarser feather-like microstructure,characterized by a dendritic framework with inter-dendritic equiaxed crystals.Concurrently,both the hardness and wear resistance of the coating decrease.Nevertheless,all Y_(2)O_(3)-modified coatings surpass the undoped Fe45 coating in both hardness and wear resistance.Appropriate Y_(2)O_(3) doping effectively refines the Fe45 alloy coating's microstru cture and induces lattice distortion,thereby enhancing its hardness and wear resistance.展开更多
Oleaginous yeasts hold significant potential as biodiesel feedstocks as they accumulate high content of lipids with similar fatty acid profiles to those of plant oils.However,the commercialization of yeast lipids is l...Oleaginous yeasts hold significant potential as biodiesel feedstocks as they accumulate high content of lipids with similar fatty acid profiles to those of plant oils.However,the commercialization of yeast lipids is limited by the high cost of nutrients for yeast cultivation.This study aimed to explore the use of agro-industrial carbon wastes as low-cost nutrients and cultivation strategies for promising oleaginous yeasts.Four oleaginous yeasts were screened for their ability to grow on molasses,crude glycerol,and whey lactose.Among the yeast strains and agro-industrial wastes tested,Candida tropicalis X37 and Rhodotorula mucilaginosa G43 grew best on molasses and produced higher lipids than other strains.Both strains grew better when adding ammonium sulfate as a low-cost nitrogen source,but C.tropicalis X37 produced higher lipids when using only molasses.Through the fed-batch cultivation,C.tropicalis X37 could thrive in high molasses concentration and gave higher biomass and lipids than R.mucilaginosa G43.Scaling up in a bioreactor using an aeration rate of 1.0 air volume per liquid volume per minute further increased the production of biomass and lipids by C.tropicalis X37 up to 15.75±0.42 g/L and 6.55±0.35 g/L,respectively.The analysis of prospective fuel properties confirmed that the yeast lipids are suitable as biodiesel feedstocks.These strategies would contribute greatly to supporting green energy supply,sustainable management of wastes,and environmental protection.展开更多
The effect of warm rolling temperature(500-900℃)on the microstructure and mechanical properties was investigated for a Ni-W-Co-Ta alloy to achieve excellent strength-plasticity synergy.The results showed that the all...The effect of warm rolling temperature(500-900℃)on the microstructure and mechanical properties was investigated for a Ni-W-Co-Ta alloy to achieve excellent strength-plasticity synergy.The results showed that the alloy exhibited high-density dislocations and deformation bands when rolled below 750℃.The nano-Ni4W phase precipitated when rolled at 700-900℃,with the higher deformation temperature,the amount and size of precipitates increased.At 900℃,dissolution of the precipitated Ni4W and dynamic recrystallization of the matrix occurred.Consequently,the strength and hardness firstly decreased,then increased,and decreased again as the deformation temperature increased.An excellent strength-plasticity synergy was achieved through the combined effects of precipitation strengthening and deformation twins strengthening of Ni4W:with a tensile strength of 2010 MPa,a yield strength of 1839 MPa,a microhardness of HV 587,and an elongation of 13.2%when the alloy was warm-rolled at 750℃.展开更多
The strength-ductility trade-off in magnesium alloys remains a critical challenge urgently requiring resolution in their engineering applications.In this study,both mechanical and corrosion properties are enhanced in ...The strength-ductility trade-off in magnesium alloys remains a critical challenge urgently requiring resolution in their engineering applications.In this study,both mechanical and corrosion properties are enhanced in extruded Mg-Y-Nd-Zr alloys by Sm addition.Sm promotes dynamic recrystallization,activates non-basal slip systems and weakens basal texture intensity,leading to the sub-grain lamellar structure and rare earth texture.The EWS2 alloy exhibits an outstanding combination of high yield strength(328 MPa)and ductility(15.1%).Furthermore,the fragmented second phases in the Sm-containing alloy are uniformly distributed,reducing the subsequent corrosion driving force after micro-galvanic corrosion and facilitating the growth of a more passivating and compact corrosion film.These combined effects contribute to the lowest degradation rate in the EWS2 alloy.This study demonstrates the correlation between microstructure and properties in Sm-containing WE series alloys,providing insights for the design of other high performance magnesium alloys.展开更多
Cryogenic rolling impacts on microstructure and mechanical properties of spray-formed 7055(SF-7055)Al alloy were investigated.Results show that with the increase of the reduction from 20%to 80%,the grain of cryogenic ...Cryogenic rolling impacts on microstructure and mechanical properties of spray-formed 7055(SF-7055)Al alloy were investigated.Results show that with the increase of the reduction from 20%to 80%,the grain of cryogenic rolled SF-7055 Al alloy is elongated to form a fiber texture.Numerous proliferating dislocations in the microstructure accumulate into dislocation walls and cells,and eventually form subgrains.These subgrain boundaries divide the original grain,thereby reducing the grain size.Under severe deformation conditions,they even enable the formation of nanograins.Meanwhile,the Cu-rich precipitates in the matrix are also broken and refined under the action of large rolling stress.In the process of cryogenic rolling,the tensile strength and hardness of SF-7055 Al alloy gradually increase,while the plasticity decreases.Moreover,the fracture morphology of cryogenic rolled SF-7055 Al alloy gradually transforms to the ductile and quasi-cleavage hybrid fracture characteristics with increased reduction.展开更多
基金supported by the National Natural Science Foundation of China(Nos.92166105 and 52005053)High-Tech Industry Science and Technology Innovation Leading Program of Hunan Province(No.2020GK2085)the Science and Technology Innovation Program of Hunan Province(No.2021RC3096).
文摘(NbZrHfTi)C high-entropy ceramics,as an emerging class of ultra-high-temperature materials,have garnered significant interest due to their unique multi-principal-element crystal structure and exceptional hightemperature properties.This study systematically investigates the mechanical properties of(NbZrHfTi)C high-entropy ceramics by employing first-principles density functional theory,combined with the Debye-Grüneisen model,to explore the variations in their thermophysical properties with temperature(0–2000 K)and pressure(0–30 GPa).Thermodynamically,the calculated mixing enthalpy and Gibbs free energy confirm the feasibility of forming a stable single-phase solid solution in(NbZrHfTi)C.The calculated results of the elastic stiffness constant indicate that the material meets the mechanical stability criteria of the cubic crystal system,further confirming the structural stability.Through evaluation of key mechanical parameters—bulk modulus,shear modulus,Young’s modulus,and Poisson’s ratio—we provide comprehensive insight into the macro-mechanical behaviour of the material and its correlation with the underlying microstructure.Notably,compared to traditional binary carbides and their average properties,(NbZrHfTi)C exhibits higher Vickers hardness(Approximately 28.5 GPa)and fracture toughness(Approximately 3.4 MPa⋅m^(1/2)),which can be primarily attributed to the lattice distortion and solid-solution strengthening mechanism.The study also utilizes the quasi-harmonic approximation method to predict the material’s thermophysical properties,including Debye temperature(initial value around 563 K),thermal expansion coefficient(approximately 8.9×10^(−6) K−1 at 2000 K),and other key parameters such as heat capacity at constant volume.The results show that within the studied pressure and temperature ranges,(NbZrHfTi)C consistently maintains a stable phase structure and good thermomechanical properties.The thermal expansion coefficient increasing with temperature,while heat capacity approaches the Dulong-Petit limit at elevated temperatures.These findings underscore the potential of(NbZrHfTi)C applications in ultra-high temperature thermal protection systems,cutting tool coatings,and nuclear structural materials.
基金Supported by National Natural Science Foundation of China(50976032,51776070)。
文摘Oxygen carriers play a fundamental role in chemical looping combustion(CLC).Iron-based carriers have been extensively investigated owing to their abundance and environmentally friendly.However,the reactivity and separability of iron-based carriers require further enhancement.This study investigates the effect of the concentration of Mn doping on reactivity,elastic properties and magnetic properties based on density functional theory(DFT)calculations.Theoretical results demonstrate that Mn doping effectively enhances reactivity by reducing the oxygen vacancy formation energy(E_(vac))from 2.33 to 0.87 eV.However,Mn doping introduces HV/EV Ms lattice distortions that deteriorate elastic properties,thereby reducing wear resistance,as evidenced by a 54.54%decrease in the hardness-to-Young's modulus ratio(H_(v)/E_(v))forα-Fe_(2)O_(3)and an 83.33%reduction for Fe_(3)O_(4).Furthermore,Mn doping also modifies magnetic properties.The maximum of saturation magnetization(M_(s))of Fe_(3)O_(4)reaches 121.02 emu/g at 33.33%Mn doping concentration.Finally,systematic evaluation identifies 33.33%as the optimal Mn doping concentration,achieving a balance in enhanced reactivity,superior magnetic performance,and retained elastic stability.
基金financially supported by the National Nat-ural Science Foundation of China(No.52404337)the Chun-hui Plan Collaborative Research Project from Chinese Edu-cation Ministry(No.HZKY20220036)+1 种基金the Guangdong Ba-sic and Applied Basic Research Foundation,China(No.2022A1515110062)the Young Elite Scientists Spon-sorship Program by China Association for Science and Tech-nology(No.YESS20220231).
文摘SiO_(2)–CaO–Al_(2)O_(3)ternary inclusions are among the most common complex oxide inclusions in steel.Nevertheless,the chemical and physical properties of these composite inclusions,particularly with detailed composition changes,have not been sufficiently investigated.In this study,first-principles density functional theory calculations were used to determine the electronic,mechanical,and thermodynamic properties of two stable phases in the SiO_(2)–CaO–Al_(2)O_(3)ternary inclusion system:anorthite(CaAl_(2)Si_(2)O_(8))and gehlenite(Ca_(2)Al_(2)SiO_(7)).Based on the electronic density of states analysis and band structure calculations,oxygen atoms play important roles in the electron reactivity of both phases.Young’s modulus and Poisson’s ratios were calculated and compared with those of the SiO_(2)–CaO inclusions.The Young’s moduli of CaAl_(2)Si_(2)O_(8)(101.32 GPa)and Ca_(2)Al_(2)SiO_(7)(131.43 GPa)were close to the maximum and minimum Young’s moduli of the binary oxide inclusions,respectively.With increasing temperature,the Young’s moduli of CaAl_(2)Si_(2)O_(8)and Ca_(2)Al_(2)SiO_(7)showed slight increasing and decreasing trends,respectively,whereas the Poisson’s ratio decreased.Furthermore,the thermodynamic properties,particularly temperature-related thermal expansion coefficients,were also deeply investigated.The thermal expansion coefficients of both CaAl_(2)Si_(2)O_(8)and Ca_(2)Al_(2)SiO_(7)increased rapidly with increasing temperature in the low-temperature regime above 300K.As the temperature increased,the increasing trend slowed.When the temperature reached 2000 K,the thermal expansion coefficients of CaAl_(2)Si_(2)O_(8)and Ca_(2)Al_(2)SiO_(7)respectively were 12×10^(−6)and 8.5×10^(−6)K^(−1).These findings enhance the understanding of the physical nature of ternary inclusions in steels and provide a scientific foundation for analyzing their effects on steel performance using a more comprehensive inclusion database,thereby contributing to inclusion engineering in the development of materials with superior mechanical integrity.
基金supported by the National Natural Science Foundation of China (No.82174074)。
文摘This study investigates the properties of high-purity starches extracted from Polygonum multiflorum(PMS)and Smilax glabra(SGS).The starches were characterized by scanning electron microscopy,Fouriertransform infrared spectroscopy,X-ray diffraction,high-performance anion-exchange chromatography,and differential scanning calorimetry.Significant differences were observed in their morphological,physicochemical,and functional properties.PMS had a smaller particle size(13.68 μm),irregular polygonal shape,A-type,lower water absorption(62.67 %),and higher oil absorption(51.17 %).In contrast,SGS exhibited larger particles(31.75 μm),a nearly spherical shape,B-type,higher crystallinity(50.66 %),and greater amylose content(21.54 %),with superior thermal stability,shear resistance,and gelatinization enthalpy.SGS also contained higher resistant starch(83.28 %) and longer average chain length(20.58 %),but showed lower solubility,swelling power,light transmittance,and freeze-thaw stability.The physicochemical properties differences in crystal pattern and particle morphology between PMS and SGS lead to distinct behaviors during in vitro digestion and fermentation.These findings highlight the potential of medicinal plant starches in functional ingredients and industrial processes.
基金National Natural Science Foundation of China(51774179)Natural Science Foundation of Liaoning Province(20180550546)+2 种基金Joint Fund of State Key Laboratory of Metal Material for Marine Equipment and Application(HGSKL-USTLN(2021)03)High-Level Talent Fund of USTL(6003000377,6003000294)supported by Liaoning Provincial Department of Education(LJ212410146037)。
文摘The effect of element Ti on the microstructures and mechanical properties of as-cast and annealed NbTaMoWTi,(x=0,1,1.5,2)refractory high-entropy alloys(RHEAs)was investigated.Results show that after Ti addition,the as-cast alloys maintain their original single body-centered cubic(bcc)structure.As for the mechanical properties,compared with those without Ti addition,the strength and ductility of NbTaMoWTi,alloys increase by 93%and 215%,respectively.Furthermore,the NbTaMoWTi alloys exhibit outstanding thermal stability.After annealing at 1400 C,they still maintain the single bcc structure,and their mechanical properties are even slightly improved.However,annealing leads to a significant deterioration in the mechanical properties of high-Ti-content alloys(NbTaMoWTil and NbTaMoWTi2),owing to the formation of Ti-rich acicular phases.
文摘The strength and damping properties of Co-Ni-Cr-Mo-based alloys with 0.5wt%Nb addition after various plastic deformation and heat treatment processes were investigated.Through Vickers hardness tests,free resonance Young's modulus measurements,and microstructure analysis,the effects of dislocation density,vacancy formation,and recrystallization on the alloy performance were clarified.Results indicate that increasing the rolling reduction enhances damping property due to higher dislocation density,whereas aging below the recrystallization temperature reduces damping property via dislocation pinning by the Suzuki effect.Recrystallization heat treatment restores the original structure and damping level.This alloy possesses tensile strength of approximately 1500 MPa and logarithmic decrement valueδ^(-1) in the range of 2×10^(-4)–3×10^(-4),demonstrating superior mechanical properties compared with the Ti-based alloys,which makes it an excellent candidate material for ultrasonic tools and medical applications.
文摘Three zinc(Ⅱ),nickel(Ⅱ),and cadmium(Ⅱ)complexes,namely[Zn(μ-Htpta)(py)_(2)]n(1),[Ni(H_(2)biim)2(H_(2)O)2][Ni(tpta)(H_(2)biim)2(H_(2)O)]2·3H_(2)O(2),and[Cd_(3)(μ4-tpta)2(μ-dpe)_(3)]_(n)(3),have been constructed hydrothermally at 160℃ using H_(3)tpta([1,1':3',1″-terphenyl]-4,4',5'-tricarboxylic acid),py(pyridine),H_(2)biim(2,2'-biimidazole),dpe(1,2-di(4-pyridyl)ethylene),and zinc,nickel and cadmium chlorides,resulting in the formation of stable crystalline solids which were subsequently analyzed using infrared spectroscopy,element analysis,thermogravimetric analysis,as well as structural analyses conducted via single-crystal X-ray diffraction.The findings from these single-crystal Xray diffraction studies indicate that complexes 1-3 form crystals within the monoclinic system P2_(1)/c space group(1)or triclinic system P1 space group(2 and 3),and possess 1D,0D,and 3D structures,respectively.Complex 1 demonstrated substantial catalytic efficiency and excellent reusability as a heterogeneous catalyst in the reaction of Knoevenagel condensation under ambient temperature conditions.In addition,complex 1 also showcased notable anti-wear performance when used in polyalphaolefin synthetic lubricants.CCDC:2449810,1;2449811,2;2449812,3.
文摘Dissimilar AZ31B magnesium alloy and DC56D steel were welded via AA1060 aluminum alloy by magnetic pulse welding.The effects of primary and secondary welding processes on the welded interface were comparatively investigated.Macroscopic morphology,microstructure,and interfacial structure of the joints were analyzed using scanning electron microscope,energy dispersive spectrometer,and X-ray diffractometer(XRD).The results show that magnetic pulse welding of dissimilar Mg/Fe metals is achieved using an Al interlayer,which acts as a bridge for deformation and diffusion.Specifically,the AZ31B/AA1060 interface exhibits a typical wavy morphology,and a transition zone exists at the joint interface,which may result in an extremely complex microstructure.The microstructure of this transition zone differs from that of AZ31B magnesium and 1060 Al alloys,and it is identified as brittle intermetallic compounds(IMCs)Al_(3)Mg_(2) and Al_(12)Mg_(17).The transition zone is mainly distributed on the Al side,with the maximum thickness of Al-side transition layer reaching approximately 13.53μm.Incomplete melting layers with varying thicknesses are observed at the primary weld interface,while micron-sized hole defects appear in the transition zone of the secondary weld interface.The AA1060/DC56D interface is mainly straight,with only a small number of discontinuous transition zones distributed intermittently along the interface.These transition zones are characterized by the presence of the brittle IMC FeAl_(3),with a maximum thickness of about 4μm.
基金supported by National Key R&D Program of China (2022YFD1900104)。
文摘To maintain soil quality under long-term saline water irrigation,the influence of manure on soil physical properties was examined.Long-term saline irrigation has been conducted from 2015 to 2024 at the Nanpi Eco-Agricultural Experimental Station of Chinese Academy Sciences in the Low Plain of the North China Plain,comprising four irrigation treatments:irrigation once at the jointing stage for winter wheat with irrigation water containing salt at fresh water,3,4 and 5 g·L^(–1),and maize irrigation at sowing using fresh water.Manure application was conducted under all irrigation treatments,with treatments without manure application used as controls.The results showed that under long-term irrigation with saline water,the application of manure increased the soil organic matter content,exchangeable potassium,available phosphorus,and total nitrogen content in the 0–20 cm soil layer by 46.8%,117.0%,75.7%,and 45.5%,respectively,compared to treatments without manure application.The application of manure reduced soil bulk density.It also increased the proportion of water-stable aggregates and the abundance of bacteria,fungi,and actinomycetes in the tillage soil layer compared to the controls.Because of the salt contained in the manure,the application of manure had dual effects on soil salt content.During the winter wheat season,manure application increased soil salt content.The salt content was significantly reduced during the summer maize season,owing to the strong salt-leaching effects under manure application,resulting in a smaller difference in salt content between the manure and non-manure treatments.During the summer rainfall season,improvements in soil structure under manure application increased the soil desalination rate for the 1 m top soil layer.The desalination rate for 0–40 cm and 40–100 cm was averagely by 39.1%and 18.9%higher,respectively,under manure application as compared with that under the nomanure treatments.The yield of winter wheat under manure application was 0.12%lower than that of the control,owing to the higher salt content during the winter wheat season.In contrast,the yield of summer maize improved by 3.9%under manure application,owing to the increased soil nutrient content and effective salt leaching.The results of this study indicated that manure application helped maintain the soil physical structure,which is important for the long-term use of saline water.In practice,using manure with a low salt content is suggested to reduce the adverse effects of saline water irrigation on soil properties and achieve sustainable saline water use.
基金National Natural Science Foundation of China(U24A2038)。
文摘The effects of channel segregation on the macro-and micro-scale chemical composition,microstructure,hardness,and tensile deformation behavior of Ti45Nb wires were investigated.The results show that wires with severe channel segregation exhibit a macroscopic chemical composition identical to those without segregation,and 3D X-ray imaging result also reveals no abnormalities.After annealing,both types of wires exhibit an equiaxed single-phase microstructure with comparable grain sizes,suggesting that channel segregation has negligible influence on the macroscopic composition and grain size.Metallographic examination reveals that channel segregation manifests as spot-like features in the transverse section and band-like structures in the longitudinal section.EDS analysis identifies these regions as Ti-enriched segregations,with a Ti content higher than that of the surrounding matrix by approximately 4.42wt%.Compared to segregation-free wires,those containing extensive channel segregation demonstrate a 15.5%increase in ultimate tensile strength and a 12.3%increase in yield strength,but suffer a reduction in elongation and reduction of area by 19.8%and 18.9%,respectively.Furthermore,the mechanical properties of wires with segregation show significant fluctuations.Fractographic analysis reveals a larger fracture surface area in segregated wires.Severe dislocation pile-ups occur at the interfaces of these segregated regions,initiating microcrack nucleation.This promotes rapid crack propagation of the Ti45Nb wire,leading to a significant decrease in plasticity and reduction of area.
基金financially supported by Natural Science Foundation of Shandong Province(Grant No.ZR2021ME019).
文摘Polyurea(PUA)is widely valued in protective coatings and structural reinforcement because of its impressive mechanical strength and resistance to corrosion.Its high flammability,together with the poor dispersion that often comes with simply blending in flame retardants,continues to limit its use in demanding environments.To overcome these issues,this study introduces a different approach.We grafted 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide(DOPO)onto the surface of a metal-organic framework(MOF)and then partially amino-functionalized the DOPO layer,ultimately creating an amino-modified DOPO-MOF hybrid.The introduced amino groups can directly react with the isocyanate(-NCO)groups in the PUA matrix,allowing the flame-retardant component to be integrated via reactive integration rather than physical blending.This approach helps avoid the interfacial defects and the mechanical weakening typically observed in conventional blending.With 5 wt% ZIF-67@DOPO-NH2 added to the PUA system,the composite successfully reached a UL-94 V-0 classification and showed a notable increase in limiting oxygen index(LOI),from19.2% to 23.8%.The peak heat release rate and total heat release dropped by 36.3% and 38.7%,respectively.Meanwhile,the tensile strength decreased from 25.74 to 22.52 MPa,while the elongation at break remained above 300%,indicating that the material maintained excellent toughness.
基金supported by the National Natural Science Foundation of China(Nos.U23A20610,52164017,52064011,52274331,and 521043348)the Guizhou Provincial Basic Research Program(Natural Science)(Nos.ZK[2021]258 and ZK[2023]Zhongdian 020)+6 种基金the Guizhou Provincial Program on Commercialization of Scientific and Technological Achievements(No.[2021]086)the Natural Science Research Project of Guizhou Provincial Department of Education(No.[2022]041)the Key Research Projects in Higher Education Institutions of Henan Province(No.24B450003)the Zhengzhou Railway Vocational and Technical College School Scientific Research Project(No.2024KY015)the Guizhou Province Dual-Carbon and New Energy Technology Innovation and Development Research Institute Open Project(No.DCRE-2023-01)the Guizhou Provincial Science and Technology Projects(No.GCC[2023]017)supported by the State Key Laboratory of Advanced Metallurgy(No.K23-04)。
文摘In the casting process of 1060 industrial pure aluminum,the inclusions in the aluminum melt significantly affect the product quality.In this study,the influence of refining temperature and the composition of salt fluxes on the purification effect and mechanical properties of aluminum melt was investigated.The results indicate that lower refining temperatures and modified salt fluxes can effectively enhance the cleanliness of the aluminum melt.As the refining temperature increases,the large inclusions gradually increase.The addition of16wt.%Na_(3)AlF_(6) can dissolve and break up Al_2O_(3) inclusions,facilitating the separation of the aluminum melt and aluminum slag.The addition of 16wt.%Na3AlF6 and 2wt.%CaCO_(3) to the basic salt fluxes enables gas refinement,thereby further improving the cleanliness of the aluminum melt.Under the refining condition of 37wt.%NaCl-47wt.%KCl--16wt.%Na3AIF3-2wt.%CaCO_(3) at 740℃,better cleanliness and mechanical properties were obtained.The cleanliness and yield strength are approximately 99.99928%and 71.46 MPa,respectively.This work can offer valuable reference and theoretical insights for future research.
文摘To comprehensively explore the impact of binder content on the mechanical properties of the Polymer bonded explosive(PBX)substitute material(Polymer-bonded Analogue Explosive(PAE)—it is renowned for its outstanding high-temperature resistance,exceptional mechanical properties,excellent chemical stability,and superior electrical insulation),a series of experiments are meticulously carried out.The dynamic and static mechanical properties,along with the microstructure of PAE,are precisely measured through the Split Hopkinson Pressure Bar(SHPB)test,static compression tests,and Scanning Electron Microscopy(SEM).The dynamic performance test outcomes clearly indicate that both the binder content(2%,4%,6%)and temperature(25℃,45℃,70℃)exert a substantial influence on the dynamic mechanical properties of PAE.Specifically,as the binder content increases,the elasticmodulus increases,demonstrating higher stiffness,and the longer failure duration represents a prolonged fracture process rather than an improved deformation strain to failure.This means the strength-related stiffness rises with binder content,but the overall ductility does not increase.Notably,PAE with 2%the Ethylene-Vinyl Acetate Copolymer(EVA)—it bonds well with a variety ofmaterials,such asmetal,wood,and plastic—exhibits distinct plastic deformation behavior,while PAE samples with 4%and 6%EVA display evident brittle fracture characteristics.Additionally,the mechanical properties of PAE are highly sensitive to temperature variations.Among the tested temperatures,PAE showcases the most favorable performance at 45℃.The static performance test results reveal that an increment in binder content effectively helps to reduce the temperature sensitivity of temperature(-40℃,25℃,50℃,70℃)on PAE and enhance its static mechanical properties.The maximum compressive strength gradually diminishes as the temperature rises.However,it should be noted that an excessively high binder content will undermine the mechanical properties of PAE.With the increase in binder content,the compressive modulus demonstrates relatively stable changes under both lowtemperature and high-temperature conditions.The SEM analysis results demonstrate that,aside fromthe initial defects inherent in the material preparation process,the components of PAE are firmly combined.Throughout the tests,no new pores or microcracks emerge,which strongly indicates that the mechanical properties of PAE remain stable.
基金supported by the Jiangxi Provincial Natural Science Foundation of China(Grant number 20224BAB204049)the Fund Project of Jiangxi Provincial Department of Education(Grant number GJJ2200602)the National Natural Science Foundation of China(Grant number 52205194)。
文摘The laser-clad Fe45 alloy coating inherently comprises multiple crystalline phases,resulting in a heterogeneous microstructural distribution that influences its performance.In this study,the rare earth yttria(Y_(2)O_(3))was employed to modify laser-clad Fe45 alloy coatings,and the effects of Y_(2)O_(3) addition on their microstructure,microhardness,and tribological properties were investigated.As the Y_(2)O_(3) content increases from 0%to 0.3wt.%,the dominant microstructure transforms from columnar crystals to fine cellular and equiaxed crystals.The modified coating with 0.3wt.%Y_(2)O_(3) achieves a surface hardness of 568 HV_(0.3)and a wear volume of 1,735.41 um~3,representing a 14.06%increase in hardness and a 51.16%reduction in wear volume compared to the undoped coating.Further increasing the Y_(2)O_(3) content from 0.3wt.%to 0.9wt.%gradually leads to the emergence of a coarser feather-like microstructure,characterized by a dendritic framework with inter-dendritic equiaxed crystals.Concurrently,both the hardness and wear resistance of the coating decrease.Nevertheless,all Y_(2)O_(3)-modified coatings surpass the undoped Fe45 coating in both hardness and wear resistance.Appropriate Y_(2)O_(3) doping effectively refines the Fe45 alloy coating's microstru cture and induces lattice distortion,thereby enhancing its hardness and wear resistance.
基金supported by Faculty of Agro-Industry and National Science,Research and Innovation Fund(NSRF)and Prince of Songkla University(Ref.No.AGR6701270b)National Research Council of Thailand(NRCT):Contract number N42A680491.
文摘Oleaginous yeasts hold significant potential as biodiesel feedstocks as they accumulate high content of lipids with similar fatty acid profiles to those of plant oils.However,the commercialization of yeast lipids is limited by the high cost of nutrients for yeast cultivation.This study aimed to explore the use of agro-industrial carbon wastes as low-cost nutrients and cultivation strategies for promising oleaginous yeasts.Four oleaginous yeasts were screened for their ability to grow on molasses,crude glycerol,and whey lactose.Among the yeast strains and agro-industrial wastes tested,Candida tropicalis X37 and Rhodotorula mucilaginosa G43 grew best on molasses and produced higher lipids than other strains.Both strains grew better when adding ammonium sulfate as a low-cost nitrogen source,but C.tropicalis X37 produced higher lipids when using only molasses.Through the fed-batch cultivation,C.tropicalis X37 could thrive in high molasses concentration and gave higher biomass and lipids than R.mucilaginosa G43.Scaling up in a bioreactor using an aeration rate of 1.0 air volume per liquid volume per minute further increased the production of biomass and lipids by C.tropicalis X37 up to 15.75±0.42 g/L and 6.55±0.35 g/L,respectively.The analysis of prospective fuel properties confirmed that the yeast lipids are suitable as biodiesel feedstocks.These strategies would contribute greatly to supporting green energy supply,sustainable management of wastes,and environmental protection.
基金supported by the National Key Research and Development Program of China(No.2022YFB3705200)the National Natural Science Foundation of China(Nos.U1804146,51905153,52111530068)the Major Science and Technology Project of Henan Province,China(No.221100230200)。
文摘The effect of warm rolling temperature(500-900℃)on the microstructure and mechanical properties was investigated for a Ni-W-Co-Ta alloy to achieve excellent strength-plasticity synergy.The results showed that the alloy exhibited high-density dislocations and deformation bands when rolled below 750℃.The nano-Ni4W phase precipitated when rolled at 700-900℃,with the higher deformation temperature,the amount and size of precipitates increased.At 900℃,dissolution of the precipitated Ni4W and dynamic recrystallization of the matrix occurred.Consequently,the strength and hardness firstly decreased,then increased,and decreased again as the deformation temperature increased.An excellent strength-plasticity synergy was achieved through the combined effects of precipitation strengthening and deformation twins strengthening of Ni4W:with a tensile strength of 2010 MPa,a yield strength of 1839 MPa,a microhardness of HV 587,and an elongation of 13.2%when the alloy was warm-rolled at 750℃.
基金supported by the National Natural Science Foundation of China(Nos.52201119,52371108)Frontier Exploration Project of Longmen Laboratory,China(No.LMQYTSKT014)The Joint Fund of Henan Science and Technology R&D Plan of China(No.242103810056).
文摘The strength-ductility trade-off in magnesium alloys remains a critical challenge urgently requiring resolution in their engineering applications.In this study,both mechanical and corrosion properties are enhanced in extruded Mg-Y-Nd-Zr alloys by Sm addition.Sm promotes dynamic recrystallization,activates non-basal slip systems and weakens basal texture intensity,leading to the sub-grain lamellar structure and rare earth texture.The EWS2 alloy exhibits an outstanding combination of high yield strength(328 MPa)and ductility(15.1%).Furthermore,the fragmented second phases in the Sm-containing alloy are uniformly distributed,reducing the subsequent corrosion driving force after micro-galvanic corrosion and facilitating the growth of a more passivating and compact corrosion film.These combined effects contribute to the lowest degradation rate in the EWS2 alloy.This study demonstrates the correlation between microstructure and properties in Sm-containing WE series alloys,providing insights for the design of other high performance magnesium alloys.
基金financially and technically supported by the National Key Laboratory Foundation of Science and Technology on Materials under Shock and Impact,Beijing Institute of Technology,China(No.WDZC2024-1)。
文摘Cryogenic rolling impacts on microstructure and mechanical properties of spray-formed 7055(SF-7055)Al alloy were investigated.Results show that with the increase of the reduction from 20%to 80%,the grain of cryogenic rolled SF-7055 Al alloy is elongated to form a fiber texture.Numerous proliferating dislocations in the microstructure accumulate into dislocation walls and cells,and eventually form subgrains.These subgrain boundaries divide the original grain,thereby reducing the grain size.Under severe deformation conditions,they even enable the formation of nanograins.Meanwhile,the Cu-rich precipitates in the matrix are also broken and refined under the action of large rolling stress.In the process of cryogenic rolling,the tensile strength and hardness of SF-7055 Al alloy gradually increase,while the plasticity decreases.Moreover,the fracture morphology of cryogenic rolled SF-7055 Al alloy gradually transforms to the ductile and quasi-cleavage hybrid fracture characteristics with increased reduction.
