In this paper, we analyze the enthalpy, enthalpy energy density, thermodynamic volume, and the equation of state of a modified white hole. We obtain new possible mathematical connections with some sectors of Number Th...In this paper, we analyze the enthalpy, enthalpy energy density, thermodynamic volume, and the equation of state of a modified white hole. We obtain new possible mathematical connections with some sectors of Number Theory, Ramanujan Recurring Numbers, DN Constant and String Theory, that enable us to extract the quantum geometrical properties of these thermodynamic equations and the implication to the quantum vacuum spacetime geometry of our early universe as they act as the constraints to the nature of quantum gravity of the universe.展开更多
With the legislative development,the organic and inorganic composition separation has become the primary requirement for sewer sediment disposal,however the relevant technology has been rarely reported and the driving...With the legislative development,the organic and inorganic composition separation has become the primary requirement for sewer sediment disposal,however the relevant technology has been rarely reported and the driving mechanism was still unclear.In this study,direct disintegration of biopolymers and indirect broken of connection point were investigated on the hydrolysis and component separation.Three typical sewer sediment treatment approaches,i.e.,alkaline,thermal and cation exchange treatments were proposed,which represented the hydrolysis-driving forces of chemical hydrolysis,physical hydrolysis and innovative cation bridging break-age.The results showed that the organic and inorganic separation rates of sewer sediment driven by alkaline,thermal and cation exchange treatments reached 21.26%,23.80%,and 19.56%-48.0%,respectively,compared to 4.43%in control.The secondary structure of proteins was disrupted,transitioning from𝛼α-helix to𝛽β-turn and random coil.Meanwhile,much biopolymers were released from solid to the liquid phase.From thermody-namic perspective,sewer sediment deposition was controlled by short-range interfacial interactions described by extended Derjaguin-Landau-Verwey-Overbeek theory.Additionally,the separation of organic and inorganic components was positively correlated with the thermodynamic parameters(Corr=0.87),highlighted the robust-ness of various driving forces.And the flocculation energy barriers were 2.40(alkaline),1.60 times(thermal),and 4.02–4.97 times(cation exchange)compared to control group.The findings revealed the contrition differ-ence of direct disintegration of gelatinous biopolymers and indirect breakage of composition connection sites in sediment composition separation,filling the critical gaps in understanding the specific mechanisms of sediment biopolymer disintegration and intermolecular connection breakage.展开更多
(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
The precise tuning of magnetic nanoparticle size and magnetic domains,thereby shaping magnetic properties.However,the dynamic evolution mechanisms of magnetic domain configurations in relation to electromagnetic(EM)at...The precise tuning of magnetic nanoparticle size and magnetic domains,thereby shaping magnetic properties.However,the dynamic evolution mechanisms of magnetic domain configurations in relation to electromagnetic(EM)attenuation behavior remain poorly understood.To address this gap,a thermodynamically controlled periodic coordination strategy is proposed to achieve precise modulation of magnetic nanoparticle spacing.This approach unveils the evolution of magnetic domain configurations,progressing from individual to coupled and ultimately to crosslinked domain configurations.A unique magnetic coupling phenomenon surpasses the Snoek limit in low-frequency range,which is observed through micromagnetic simulation.The crosslinked magnetic configuration achieves effective low-frequency EM wave absorption at 3.68 GHz,encompassing nearly the entire C-band.This exceptional magnetic interaction significantly enhances radar camouflage and thermal insulation properties.Additionally,a robust gradient metamaterial design extends coverage across the full band(2–40 GHz),effectively mitigating the impact of EM pollution on human health and environment.This comprehensive study elucidates the evolution mechanisms of magnetic domain configurations,addresses gaps in dynamic magnetic modulation,and provides novel insights for the development of high-performance,low-frequency EM wave absorption materials.展开更多
Using a dynamic laser monitoring technique,the solubility of 3-nitro-1,2,4-triazole-5-one(NTO)was investigated in two different binary systems,namely hydroxylamine nitrate(HAN)-water and boric acid(HB)-water ranging f...Using a dynamic laser monitoring technique,the solubility of 3-nitro-1,2,4-triazole-5-one(NTO)was investigated in two different binary systems,namely hydroxylamine nitrate(HAN)-water and boric acid(HB)-water ranging from 278.15 K to 318.15 K.The solubility in each system was found to be positively correlated with temperature.Furthermore,solubility data were analyzed using four equations:the modified Apelblat equation,Van’t Hoff equation,λh equation and CNIBS/R-K equations,and they provided satisfactory results for both two systems.The average root-mean-square deviation(105RMSD)values for these models were less than 13.93.Calculations utilizing the Van’t Hoff equation and Gibbs equations facilitated the derivation of apparent thermodynamic properties of NTO dissolution in the two systems,including values for Gibbs free energy,enthalpy and entropy.The%ζ_(H)is larger than%ζ_(TS),and all the%ζ_(H)data are≥58.63%,indicating that the enthalpy make a greater contribution than entropy to theΔG_(soln)^(Θ).展开更多
In this paper,a new efficient,and at the same time,very simple and general class of thermodynamically compatiblefinite volume schemes is introduced for the discretization of nonlinear,overdetermined,and thermodynamicall...In this paper,a new efficient,and at the same time,very simple and general class of thermodynamically compatiblefinite volume schemes is introduced for the discretization of nonlinear,overdetermined,and thermodynamically compatiblefirst-order hyperbolic systems.By construction,the proposed semi-discrete method satisfies an entropy inequality and is nonlinearly stable in the energy norm.A very peculiar feature of our approach is that entropy is discretized directly,while total energy conservation is achieved as a mere consequence of the thermodynamically compatible discretization.The new schemes can be applied to a very general class of nonlinear systems of hyperbolic PDEs,including both,conservative and non-conservative products,as well as potentially stiff algebraic relaxation source terms,provided that the underlying system is overdetermined and therefore satisfies an additional extra conservation law,such as the conservation of total energy density.The proposed family offinite volume schemes is based on the seminal work of Abgrall[1],where for thefirst time a completely general methodology for the design of thermodynamically compatible numerical methods for overdetermined hyperbolic PDE was presented.We apply our new approach to three particular thermodynamically compatible systems:the equations of ideal magnetohydrodynamics(MHD)with thermodynamically compatible generalized Lagrangian multiplier(GLM)divergence cleaning,the unifiedfirst-order hyperbolic model of continuum mechanics proposed by Godunov,Peshkov,and Romenski(GPR model)and thefirst-order hyperbolic model for turbulent shallow waterflows of Gavrilyuk et al.In addition to formal mathematical proofs of the properties of our newfinite volume schemes,we also present a large set of numerical results in order to show their potential,efficiency,and practical applicability.展开更多
Thermodynamic modeling is still themostwidely usedmethod to characterize aerosol acidity,a critical physicochemical property of atmospheric aerosols.However,it remains unclear whether gas-aerosol partitioning should b...Thermodynamic modeling is still themostwidely usedmethod to characterize aerosol acidity,a critical physicochemical property of atmospheric aerosols.However,it remains unclear whether gas-aerosol partitioning should be incorporated when thermodynamicmodels are employed to estimate the acidity of coarse particles.In this work,field measurements were conducted at a coastal city in northern China across three seasons,and covered wide ranges of temperature,relative humidity and NH_(3) concentrations.We examined the performance of different modes of ISORROPIA-II(a widely used aerosol thermodynamic model)in estimating aerosol acidity of coarse and fine particles.The M0 mode,which incorporates gas-phase data and runs the model in the forward mode,provided reasonable estimation of aerosol acidity for coarse and fine particles.Compared to M0,the M1 mode,which runs the model in the forward mode but does not include gas-phase data,may capture the general trend of aerosol acidity but underestimates pH for both coarse and fine particles;M2,which runs the model in the reverse mode,results in large errors in estimated aerosol pH for both coarse and fine particles and should not be used for aerosol acidity calculations.However,M1 significantly underestimates liquid water contents for both fine and coarse particles,while M2 provides reliable estimation of liquid water contents.In summary,our work highlights the importance of incorporating gas-aerosol partitioning when estimating coarse particle acidity,and thus may help improve our understanding of acidity of coarse particles.展开更多
Magnesium(Mg)alloys are widely used lightweight structural materials for automobiles and help reduce carbon emissions.However,their use increases the production of Mg alloy scrap,which is recycled at a much lower rate...Magnesium(Mg)alloys are widely used lightweight structural materials for automobiles and help reduce carbon emissions.However,their use increases the production of Mg alloy scrap,which is recycled at a much lower rate than aluminum,and its greater complexity poses challenges to existing recycling processes.Although vacuum distillation can be used to recycle Mg alloy scrap,this requires optimizing and maximizing metal recirculation,but there has been no thermodynamic analysis of this process.In this study,the feasibility and controllability of separating inclusions and 23 metal impurities were evaluated,and their distribution and removal limits were quantified.Thermodynamic analyses and experimental results showed that inclusions and impurity metals of separation coefficient lgβ_(i)≤-5,including Cu,Fe,Co,and Ni below 0.001 ppm,could be removed from the matrix.All Zn entered the recycled Mg,while impurities with-1<lgβ_(i)<-5 such as Li,Ca,and Mn severely affected the purity of the recycled Mg during the later stage of distillation.Therefore,an optimization strategy for vacuum distillation recycling:lower temperatures and higher system pressures for Zn separation in the early stage,and the early termination of the recovery process in the later stage or a continuous supply of raw melt can also prevent contamination during recycling.The alloying elements Al and Zn in Mg alloy scrap can be further recovered and purified by vacuum distillation when economically feasible,to maximize the recycling of metal resources.展开更多
In this work,silicon-carbon hybrid materials were adopted as an example to illustrate the novel strategy to in situ construct heterostructure with adjustable microstructure.Based on the temperature-dependent thermodyn...In this work,silicon-carbon hybrid materials were adopted as an example to illustrate the novel strategy to in situ construct heterostructure with adjustable microstructure.Based on the temperature-dependent thermodynamics and kinetics of reaction between Si and C,the processes for Si nanocrystals growth and C decoration were coupled at different zones of plasma flame according to its temperature and velocity fields by theoretical modeling,aiming to intentionally suppress the formation of undesirable carbide,and enable adjusting the microstructure of each counterpart separately in transient process.As a result,well-controlled Si/C nanocomposites,including nanospheres and nanowires with core-shell structures,were achieved,and this continuous and in-flight route is also potential for large-scale production.Further investigation on the electrochemical properties highlights the advantage of as proposed strategy to efficiently construct heterostructures with superior performance for various applications.展开更多
The mechanical and thermodynamic properties of W-Ti alloys(including W_(15)Ti_(1),W_(14)Ti_(2),W_(12)Ti_(4) and W_(8)Ti_(8) alloys)were investigated by the first-principles approach based on density functional theory....The mechanical and thermodynamic properties of W-Ti alloys(including W_(15)Ti_(1),W_(14)Ti_(2),W_(12)Ti_(4) and W_(8)Ti_(8) alloys)were investigated by the first-principles approach based on density functional theory.The results indicate that W-Ti alloys except W_(8)Ti_(8) are thermodynamically stable.The modulus and hardness of W-Ti alloys are smaller than those of pure tungsten and gradually decrease with increasing Ti concentration.However,their B/G ratios and Poisson's ratios exceed those of pure tungsten,suggesting that the introduction of Ti decreases the mechanical strength while enhancing the ductility of W-Ti alloys.The thermal expansion coefficients for W-Ti alloys all surpass those of pure tungsten,indicating that the introduction of titanium exacerbates the thermal expansion behavior of W-Ti alloys.Nevertheless,elevated pressure has the capacity to suppress the thermal expansion tendencies in titanium-doped tungsten alloys.This study offers theoretical insights for the design of nuclear materials by exploring the mechanical and thermodynamic properties of W-Ti alloys.展开更多
Magnesium and magnesium alloys,serving as crucial lightweight structural materials and hydrogen storage elements,find extensive applications in space technology,aviation,automotive,and magnesium-based hydrogen industr...Magnesium and magnesium alloys,serving as crucial lightweight structural materials and hydrogen storage elements,find extensive applications in space technology,aviation,automotive,and magnesium-based hydrogen industries.The global production of primary magnesium has reached approximately 1.2 million tons per year,with anticipated diversification in future applications and significant market demand.Nevertheless,approximately 80%of the world’s primary magnesium is still manufactured through the Pidgeon process,grappling with formidable issues including high energy consumption,massive carbon emission,significant resource depletion,and environmental pollution.The implementation of the relative vacuum method shows potential in breaking through technological challenges in the Pidgeon process,facilitating clean,low-carbon continuous magnesium smelting.This paper begins by introducing the principles of the relative vacuum method.Subsequently,it elucidates various innovative process routes,including relative vacuum ferrosilicon reduction,aluminum thermal reduction co-production of spinel,and aluminum thermal reduction co-production of calcium aluminate.Finally,and thermodynamic foundations of the relative vacuum,a quantitative analysis of the material,energy flows,carbon emission,and production cost for several new processes is conducted,comparing and analyzing them against the Pidgeon process.The study findings reveal that,with identical raw materials,the relative vacuum silicon thermal reduction process significantly decreases raw material consumption,energy consumption,and carbon dioxide emissions by 15.86%,30.89%,and 26.27%,respectively,compared to the Pidgeon process.The relative vacuum process,using magnesite as the raw material and aluminum as the reducing agent,has the lowest magnesium-to-feed ratio,at only 3.385.Additionally,its energy consumption and carbon dioxide emissions are the lowest,at 1.817 tce/t Mg and 7.782 t CO_(2)/t Mg,respectively.The energy consumption and carbon emissions of the relative vacuum magnesium smelting process co-producing calcium aluminate(12CaO·7Al_(2)O_(3),3CaO·Al_(2)O_(3),and CaO·Al_(2)O_(3))are highly correlated with the consumption of dolomite in the raw materials.When the reduction temperature is around 1473.15 K,the critical volume fraction of magnesium vapor for different processes varies within the range of 5%–40%.Production cost analysis shows that the relative vacuum primary magnesium smelting process has significant economic benefits.This paper offers essential data support and theoretical guidance for achieving energy efficiency,carbon reduction in magnesium smelting,and the industrial adoption of innovative processes.展开更多
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
This work investigates the potential of low-pressure,medium-speed dual-fuel engines for cleaner maritime transportation.The thermodynamic performance of these engines is explored using three alternative fuels:liquefie...This work investigates the potential of low-pressure,medium-speed dual-fuel engines for cleaner maritime transportation.The thermodynamic performance of these engines is explored using three alternative fuels:liquefied natural gas(LNG),methanol,and ammonia.A parametric analysis examines the effect of adjustments to key engine parameters(compression ratio,boost pressure,and air-fuel ratio)on performance.Results show an initial improvement in performance with an increase in compression ratio,which reaches a peak and then declines.Similarly,increases in boost pressure and air-fuel ratio lead to linear performance gains.However,insufficient cooling reduces the amount of fuel burned,which hinders performance.Exergy analysis reveals significant exergy destruction within the engine,which ranges from 69.96%(methanol)to 78.48%(LNG).Notably,the combustion process is the leading cause of exergy loss.Among the fuels tested,methanol exhibits the lowest combustion-related exergy destruction(56.41%),followed by ammonia(62.12%)and LNG(73.77%).These findings suggest that methanol is a promising near-term alternative to LNG for marine fuel applications.展开更多
Ti-V-Fe-Mn body-centered cubic(BCC)solid solution alloys arouse extensive interests due to the superb hydrogen storage capacity.Understanding phase equilibrium that involves BCC phase is important when designing hydro...Ti-V-Fe-Mn body-centered cubic(BCC)solid solution alloys arouse extensive interests due to the superb hydrogen storage capacity.Understanding phase equilibrium that involves BCC phase is important when designing hydrogen storage materials.However,a reliable thermodynamic description of Ti-V-Fe-Mn system is lacking.To support thermodynamic modeling,ab initio calculations were conducted to determine formation enthalpies of theσand C14 Laves phases.The phase equilibria of Ti-V-Fe alloys at 1273 K and Ti-V-Mn alloys at 1273,1323 and 1373 K were investigated to elucidate the relationship between the BCC and C14 Laves phases.The thermodynamic parameters for the Ti-V-Fe system were revised.The thermodynamic description of the Ti-V-Mn system was established for the first time.Additionally,the V-Mn and V-Fe-Mn systems were thermodynamically reassessed for ensuring consistency in theσphase model.The computed results were comprehensively compared with experimental data,validating that model parameters were reliable.Furthermore,the thermodynamic database for the Ti-V-Fe-Mn system was adopted for predicting phase constitutions of as-cast hydrogen storage alloys,further demonstrating the practical applicability and reliability of the model parameters.展开更多
Density(p),speed of sound(u),viscosity(η),and refractive index(n_(D))were measured for pure acetonitrile,trichloroethene,and tetrachloroethene,as well as their binary mixtures at temperatures T=(293.15,298.15,303.15)...Density(p),speed of sound(u),viscosity(η),and refractive index(n_(D))were measured for pure acetonitrile,trichloroethene,and tetrachloroethene,as well as their binary mixtures at temperatures T=(293.15,298.15,303.15)K and at ambient pressure(81.5 kPa).From the experimental data,excess molar volume(V_(m)~E),thermal expansion coefficients(α),deviations in isentropic compressibility(Δκ_(S)),viscosity(Δ_η),and refractive index(Δn_(D))were calculated.These values were then correlated using the Redlich-Kister polynomial equation,with fitting coefficients and standard deviations determined.Additionally,the Prigogine-Flory-Patterson(PFP)theory and the Extended Real Associated Solution(ERAS)model were employed to correlate the excess molar volume,while the Perturbed Chain Statistical Associating Fluid Theory(PC-SAFT)was used to predict the density of mixtures.展开更多
The comprehension of universal thermodynamic behaviors in the supercritical region is crucial for examining the characteristics of black hole systems under high temperature and pressure.This study is devoted to the an...The comprehension of universal thermodynamic behaviors in the supercritical region is crucial for examining the characteristics of black hole systems under high temperature and pressure.This study is devoted to the analysis of characteristic lines and crossover behaviors within the supercritical region.By making use of the free energy,we introduce three key thermodynamic quantities:scaled variance,skewness,and kurtosis.Our results demonstrate that the Widom line,associated with the maximal scaled variance,can effectively differentiate between small and large black hole-like subphases,each displaying distinct thermodynamic behaviors within the supercritical region.Furthermore,by utilizing quasinormal modes,we identify the Frenkel line,offering a dynamic perspective to distinguish between small and large black hole-like subphases.These contribute to a deeper comprehension of black hole subphases in the supercritical region,thus illuminating new facets of black hole thermodynamics.展开更多
The thermal effects,spontaneity and proceeding degree of 32 chemical reactions during coal reductive decomposition phosphogypsum(PG)to prepare CaO and SO_(2)are analyzed utilizing thermodynamic theory and method.The i...The thermal effects,spontaneity and proceeding degree of 32 chemical reactions during coal reductive decomposition phosphogypsum(PG)to prepare CaO and SO_(2)are analyzed utilizing thermodynamic theory and method.The ideal reaction temperature for PG decomposition and desulfurization is 1173-1273 K.The 10 key chemical reactions controlling coal reductive decomposition PG have been selected.The heat release of critical exothermic reactions can satisfy the autothermal operation of PG decomposition and desulfurization process.Meanwhile,the spontaneity of oxidation reactions has thermodynamically priority over reduction reactions.But the reaction mechanism shows that the oxidation of CaS by O_(2)is in parallel competition with the reduction of CaSO_(4)by CO and C.Furthermore,clarifying the regulatory mechanisms of PG decomposition temperature and reaction atmosphere(reducibility and oxidation)is beneficial for maximizing the production of CaO and SO_(2).展开更多
A principle was proposed for designing a method to seal anodized aluminum used in semiconductor processing apparatuses.Thermodynamic calculations and Fick’s second law were used to reveal trends in the metal ion depo...A principle was proposed for designing a method to seal anodized aluminum used in semiconductor processing apparatuses.Thermodynamic calculations and Fick’s second law were used to reveal trends in the metal ion deposition,deposition product stability,vapor pressures of halides for selected metal ions,the holding temperature,and time.Interactions between ion concentrations and the sealing temperature were also revealed.According to the design principles,anodized aluminum dipped in 1 mM Cr^(3+)ion solution and steam-sealed for 18 h exhibited the highest corrosion resistance when exposed to 5 wt.%HCl solution and HCl gas,verifying the designed results.展开更多
Mg-Zn-Mn alloys have the advantages of low cost,excellent mechanical properties,and high corrosion resistance.To clarify the phase equilibria of Mg-Zn-Mn alloy in the Mg-rich corners,the present work experimentally in...Mg-Zn-Mn alloys have the advantages of low cost,excellent mechanical properties,and high corrosion resistance.To clarify the phase equilibria of Mg-Zn-Mn alloy in the Mg-rich corners,the present work experimentally investigated the phase equilibria in the Mg-rich corner at 300-400°C with equilibrated alloy method using electron probe micro analyzer(EPMA),X-ray diffractometer(XRD),transmission electron microscopy(TEM),and differential scanning calorimeter(DSC).Mn atoms were found to dissolve into MgZn_(2) to form a ternary solid-solution type compound,in which Mn content can be up to 15.1at%at 400°C.Three-phase equilibrium ofα-Mg+MgZn_(2)+α-Mn and liquid+α-Mg+MgZn_(2) were confirmed at 400°C.Subsequently,thermodynamic modeling of the Mg-Zn-Mn system was carried out using the CALPHAD method based on the experimental data of this work and literature data.The calculated invariant reaction Liquid+α-Mn→α-Mg+MgZn_(2) at 430°C shows good agreement with the DSC results.In addition,the results of solidification path calculations explain the microstructure in the ascast and annealed alloys well.The agreement between the calculated results and experimental data proves the self-consistency of the thermodynamic database,which can provide guidance for the compositional design of Mg-Zn-Mn alloys.展开更多
文摘In this paper, we analyze the enthalpy, enthalpy energy density, thermodynamic volume, and the equation of state of a modified white hole. We obtain new possible mathematical connections with some sectors of Number Theory, Ramanujan Recurring Numbers, DN Constant and String Theory, that enable us to extract the quantum geometrical properties of these thermodynamic equations and the implication to the quantum vacuum spacetime geometry of our early universe as they act as the constraints to the nature of quantum gravity of the universe.
基金supported by Shaanxi Key Research and Development Program(No.2024SF-YBXM-546)the National Natural Science Foundation of China(No.52470161)the State Key Laboratory of Pollution Control and Resource Reuse Foundation(No.PCRRF21007).
文摘With the legislative development,the organic and inorganic composition separation has become the primary requirement for sewer sediment disposal,however the relevant technology has been rarely reported and the driving mechanism was still unclear.In this study,direct disintegration of biopolymers and indirect broken of connection point were investigated on the hydrolysis and component separation.Three typical sewer sediment treatment approaches,i.e.,alkaline,thermal and cation exchange treatments were proposed,which represented the hydrolysis-driving forces of chemical hydrolysis,physical hydrolysis and innovative cation bridging break-age.The results showed that the organic and inorganic separation rates of sewer sediment driven by alkaline,thermal and cation exchange treatments reached 21.26%,23.80%,and 19.56%-48.0%,respectively,compared to 4.43%in control.The secondary structure of proteins was disrupted,transitioning from𝛼α-helix to𝛽β-turn and random coil.Meanwhile,much biopolymers were released from solid to the liquid phase.From thermody-namic perspective,sewer sediment deposition was controlled by short-range interfacial interactions described by extended Derjaguin-Landau-Verwey-Overbeek theory.Additionally,the separation of organic and inorganic components was positively correlated with the thermodynamic parameters(Corr=0.87),highlighted the robust-ness of various driving forces.And the flocculation energy barriers were 2.40(alkaline),1.60 times(thermal),and 4.02–4.97 times(cation exchange)compared to control group.The findings revealed the contrition differ-ence of direct disintegration of gelatinous biopolymers and indirect breakage of composition connection sites in sediment composition separation,filling the critical gaps in understanding the specific mechanisms of sediment biopolymer disintegration and intermolecular connection breakage.
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 the National Natural Science Foundation of China(22265021,52231007,and 12327804)the Aeronautical Science Foundation of China(2020Z056056003)Jiangxi Provincial Natural Science Foundation(20232BAB212004).
文摘The precise tuning of magnetic nanoparticle size and magnetic domains,thereby shaping magnetic properties.However,the dynamic evolution mechanisms of magnetic domain configurations in relation to electromagnetic(EM)attenuation behavior remain poorly understood.To address this gap,a thermodynamically controlled periodic coordination strategy is proposed to achieve precise modulation of magnetic nanoparticle spacing.This approach unveils the evolution of magnetic domain configurations,progressing from individual to coupled and ultimately to crosslinked domain configurations.A unique magnetic coupling phenomenon surpasses the Snoek limit in low-frequency range,which is observed through micromagnetic simulation.The crosslinked magnetic configuration achieves effective low-frequency EM wave absorption at 3.68 GHz,encompassing nearly the entire C-band.This exceptional magnetic interaction significantly enhances radar camouflage and thermal insulation properties.Additionally,a robust gradient metamaterial design extends coverage across the full band(2–40 GHz),effectively mitigating the impact of EM pollution on human health and environment.This comprehensive study elucidates the evolution mechanisms of magnetic domain configurations,addresses gaps in dynamic magnetic modulation,and provides novel insights for the development of high-performance,low-frequency EM wave absorption materials.
文摘Using a dynamic laser monitoring technique,the solubility of 3-nitro-1,2,4-triazole-5-one(NTO)was investigated in two different binary systems,namely hydroxylamine nitrate(HAN)-water and boric acid(HB)-water ranging from 278.15 K to 318.15 K.The solubility in each system was found to be positively correlated with temperature.Furthermore,solubility data were analyzed using four equations:the modified Apelblat equation,Van’t Hoff equation,λh equation and CNIBS/R-K equations,and they provided satisfactory results for both two systems.The average root-mean-square deviation(105RMSD)values for these models were less than 13.93.Calculations utilizing the Van’t Hoff equation and Gibbs equations facilitated the derivation of apparent thermodynamic properties of NTO dissolution in the two systems,including values for Gibbs free energy,enthalpy and entropy.The%ζ_(H)is larger than%ζ_(TS),and all the%ζ_(H)data are≥58.63%,indicating that the enthalpy make a greater contribution than entropy to theΔG_(soln)^(Θ).
文摘In this paper,a new efficient,and at the same time,very simple and general class of thermodynamically compatiblefinite volume schemes is introduced for the discretization of nonlinear,overdetermined,and thermodynamically compatiblefirst-order hyperbolic systems.By construction,the proposed semi-discrete method satisfies an entropy inequality and is nonlinearly stable in the energy norm.A very peculiar feature of our approach is that entropy is discretized directly,while total energy conservation is achieved as a mere consequence of the thermodynamically compatible discretization.The new schemes can be applied to a very general class of nonlinear systems of hyperbolic PDEs,including both,conservative and non-conservative products,as well as potentially stiff algebraic relaxation source terms,provided that the underlying system is overdetermined and therefore satisfies an additional extra conservation law,such as the conservation of total energy density.The proposed family offinite volume schemes is based on the seminal work of Abgrall[1],where for thefirst time a completely general methodology for the design of thermodynamically compatible numerical methods for overdetermined hyperbolic PDE was presented.We apply our new approach to three particular thermodynamically compatible systems:the equations of ideal magnetohydrodynamics(MHD)with thermodynamically compatible generalized Lagrangian multiplier(GLM)divergence cleaning,the unifiedfirst-order hyperbolic model of continuum mechanics proposed by Godunov,Peshkov,and Romenski(GPR model)and thefirst-order hyperbolic model for turbulent shallow waterflows of Gavrilyuk et al.In addition to formal mathematical proofs of the properties of our newfinite volume schemes,we also present a large set of numerical results in order to show their potential,efficiency,and practical applicability.
基金supported by the National Natural Science Foundation of China (Nos.42022050 and 42277088)the Guangdong Basic and Applied Basic Research Fund Committee (Nos.2021A1515011248 and 2023A1515012010)the Guangdong Foundation for the Program of Science and Technology Research (No.2020B1212060053).
文摘Thermodynamic modeling is still themostwidely usedmethod to characterize aerosol acidity,a critical physicochemical property of atmospheric aerosols.However,it remains unclear whether gas-aerosol partitioning should be incorporated when thermodynamicmodels are employed to estimate the acidity of coarse particles.In this work,field measurements were conducted at a coastal city in northern China across three seasons,and covered wide ranges of temperature,relative humidity and NH_(3) concentrations.We examined the performance of different modes of ISORROPIA-II(a widely used aerosol thermodynamic model)in estimating aerosol acidity of coarse and fine particles.The M0 mode,which incorporates gas-phase data and runs the model in the forward mode,provided reasonable estimation of aerosol acidity for coarse and fine particles.Compared to M0,the M1 mode,which runs the model in the forward mode but does not include gas-phase data,may capture the general trend of aerosol acidity but underestimates pH for both coarse and fine particles;M2,which runs the model in the reverse mode,results in large errors in estimated aerosol pH for both coarse and fine particles and should not be used for aerosol acidity calculations.However,M1 significantly underestimates liquid water contents for both fine and coarse particles,while M2 provides reliable estimation of liquid water contents.In summary,our work highlights the importance of incorporating gas-aerosol partitioning when estimating coarse particle acidity,and thus may help improve our understanding of acidity of coarse particles.
文摘Magnesium(Mg)alloys are widely used lightweight structural materials for automobiles and help reduce carbon emissions.However,their use increases the production of Mg alloy scrap,which is recycled at a much lower rate than aluminum,and its greater complexity poses challenges to existing recycling processes.Although vacuum distillation can be used to recycle Mg alloy scrap,this requires optimizing and maximizing metal recirculation,but there has been no thermodynamic analysis of this process.In this study,the feasibility and controllability of separating inclusions and 23 metal impurities were evaluated,and their distribution and removal limits were quantified.Thermodynamic analyses and experimental results showed that inclusions and impurity metals of separation coefficient lgβ_(i)≤-5,including Cu,Fe,Co,and Ni below 0.001 ppm,could be removed from the matrix.All Zn entered the recycled Mg,while impurities with-1<lgβ_(i)<-5 such as Li,Ca,and Mn severely affected the purity of the recycled Mg during the later stage of distillation.Therefore,an optimization strategy for vacuum distillation recycling:lower temperatures and higher system pressures for Zn separation in the early stage,and the early termination of the recovery process in the later stage or a continuous supply of raw melt can also prevent contamination during recycling.The alloying elements Al and Zn in Mg alloy scrap can be further recovered and purified by vacuum distillation when economically feasible,to maximize the recycling of metal resources.
基金financially supported by the National Natural Science Foundation of China(No.52174342)Beijing Natural Sci-ence Foundation(No.2232044)Beijing Municipal Education Commission Research Plan General Project(No.KM202410005009).
文摘In this work,silicon-carbon hybrid materials were adopted as an example to illustrate the novel strategy to in situ construct heterostructure with adjustable microstructure.Based on the temperature-dependent thermodynamics and kinetics of reaction between Si and C,the processes for Si nanocrystals growth and C decoration were coupled at different zones of plasma flame according to its temperature and velocity fields by theoretical modeling,aiming to intentionally suppress the formation of undesirable carbide,and enable adjusting the microstructure of each counterpart separately in transient process.As a result,well-controlled Si/C nanocomposites,including nanospheres and nanowires with core-shell structures,were achieved,and this continuous and in-flight route is also potential for large-scale production.Further investigation on the electrochemical properties highlights the advantage of as proposed strategy to efficiently construct heterostructures with superior performance for various applications.
基金Funded by National Key R&D Program of China(No.2021YFB3802300)the National Natural Science Foundation of China(No.52171045)the Joint Fund(No.8091B022108)。
文摘The mechanical and thermodynamic properties of W-Ti alloys(including W_(15)Ti_(1),W_(14)Ti_(2),W_(12)Ti_(4) and W_(8)Ti_(8) alloys)were investigated by the first-principles approach based on density functional theory.The results indicate that W-Ti alloys except W_(8)Ti_(8) are thermodynamically stable.The modulus and hardness of W-Ti alloys are smaller than those of pure tungsten and gradually decrease with increasing Ti concentration.However,their B/G ratios and Poisson's ratios exceed those of pure tungsten,suggesting that the introduction of Ti decreases the mechanical strength while enhancing the ductility of W-Ti alloys.The thermal expansion coefficients for W-Ti alloys all surpass those of pure tungsten,indicating that the introduction of titanium exacerbates the thermal expansion behavior of W-Ti alloys.Nevertheless,elevated pressure has the capacity to suppress the thermal expansion tendencies in titanium-doped tungsten alloys.This study offers theoretical insights for the design of nuclear materials by exploring the mechanical and thermodynamic properties of W-Ti alloys.
基金supported by the China Postdoctoral Science Foundation(No.2023T160088)the Youth Fund of the National Natural Science Foundation of China(No.52304324).
文摘Magnesium and magnesium alloys,serving as crucial lightweight structural materials and hydrogen storage elements,find extensive applications in space technology,aviation,automotive,and magnesium-based hydrogen industries.The global production of primary magnesium has reached approximately 1.2 million tons per year,with anticipated diversification in future applications and significant market demand.Nevertheless,approximately 80%of the world’s primary magnesium is still manufactured through the Pidgeon process,grappling with formidable issues including high energy consumption,massive carbon emission,significant resource depletion,and environmental pollution.The implementation of the relative vacuum method shows potential in breaking through technological challenges in the Pidgeon process,facilitating clean,low-carbon continuous magnesium smelting.This paper begins by introducing the principles of the relative vacuum method.Subsequently,it elucidates various innovative process routes,including relative vacuum ferrosilicon reduction,aluminum thermal reduction co-production of spinel,and aluminum thermal reduction co-production of calcium aluminate.Finally,and thermodynamic foundations of the relative vacuum,a quantitative analysis of the material,energy flows,carbon emission,and production cost for several new processes is conducted,comparing and analyzing them against the Pidgeon process.The study findings reveal that,with identical raw materials,the relative vacuum silicon thermal reduction process significantly decreases raw material consumption,energy consumption,and carbon dioxide emissions by 15.86%,30.89%,and 26.27%,respectively,compared to the Pidgeon process.The relative vacuum process,using magnesite as the raw material and aluminum as the reducing agent,has the lowest magnesium-to-feed ratio,at only 3.385.Additionally,its energy consumption and carbon dioxide emissions are the lowest,at 1.817 tce/t Mg and 7.782 t CO_(2)/t Mg,respectively.The energy consumption and carbon emissions of the relative vacuum magnesium smelting process co-producing calcium aluminate(12CaO·7Al_(2)O_(3),3CaO·Al_(2)O_(3),and CaO·Al_(2)O_(3))are highly correlated with the consumption of dolomite in the raw materials.When the reduction temperature is around 1473.15 K,the critical volume fraction of magnesium vapor for different processes varies within the range of 5%–40%.Production cost analysis shows that the relative vacuum primary magnesium smelting process has significant economic benefits.This paper offers essential data support and theoretical guidance for achieving energy efficiency,carbon reduction in magnesium smelting,and the industrial adoption of innovative processes.
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.
文摘This work investigates the potential of low-pressure,medium-speed dual-fuel engines for cleaner maritime transportation.The thermodynamic performance of these engines is explored using three alternative fuels:liquefied natural gas(LNG),methanol,and ammonia.A parametric analysis examines the effect of adjustments to key engine parameters(compression ratio,boost pressure,and air-fuel ratio)on performance.Results show an initial improvement in performance with an increase in compression ratio,which reaches a peak and then declines.Similarly,increases in boost pressure and air-fuel ratio lead to linear performance gains.However,insufficient cooling reduces the amount of fuel burned,which hinders performance.Exergy analysis reveals significant exergy destruction within the engine,which ranges from 69.96%(methanol)to 78.48%(LNG).Notably,the combustion process is the leading cause of exergy loss.Among the fuels tested,methanol exhibits the lowest combustion-related exergy destruction(56.41%),followed by ammonia(62.12%)and LNG(73.77%).These findings suggest that methanol is a promising near-term alternative to LNG for marine fuel applications.
基金supported by the Natural Science Foundation of Shanghai(No.24ZR1425100)Young Elite Scientists Sponsorship Program by China Association for Science and Technology(No.YESS20210357)+1 种基金the financial supports from the open foundation of Guangxi Key Laboratory of Information Materials,Guilin University of Electronic Technology(No.211009-K)State Key Laboratory of Advanced Special Steel,Shanghai Key Laboratory of Advanced Ferrometallurgy and the Science and Technology Commission of Shanghai Municipality(No.19DZ2270200).
文摘Ti-V-Fe-Mn body-centered cubic(BCC)solid solution alloys arouse extensive interests due to the superb hydrogen storage capacity.Understanding phase equilibrium that involves BCC phase is important when designing hydrogen storage materials.However,a reliable thermodynamic description of Ti-V-Fe-Mn system is lacking.To support thermodynamic modeling,ab initio calculations were conducted to determine formation enthalpies of theσand C14 Laves phases.The phase equilibria of Ti-V-Fe alloys at 1273 K and Ti-V-Mn alloys at 1273,1323 and 1373 K were investigated to elucidate the relationship between the BCC and C14 Laves phases.The thermodynamic parameters for the Ti-V-Fe system were revised.The thermodynamic description of the Ti-V-Mn system was established for the first time.Additionally,the V-Mn and V-Fe-Mn systems were thermodynamically reassessed for ensuring consistency in theσphase model.The computed results were comprehensively compared with experimental data,validating that model parameters were reliable.Furthermore,the thermodynamic database for the Ti-V-Fe-Mn system was adopted for predicting phase constitutions of as-cast hydrogen storage alloys,further demonstrating the practical applicability and reliability of the model parameters.
基金Bu-Ali Sina University for providing financial support for conducting this study。
文摘Density(p),speed of sound(u),viscosity(η),and refractive index(n_(D))were measured for pure acetonitrile,trichloroethene,and tetrachloroethene,as well as their binary mixtures at temperatures T=(293.15,298.15,303.15)K and at ambient pressure(81.5 kPa).From the experimental data,excess molar volume(V_(m)~E),thermal expansion coefficients(α),deviations in isentropic compressibility(Δκ_(S)),viscosity(Δ_η),and refractive index(Δn_(D))were calculated.These values were then correlated using the Redlich-Kister polynomial equation,with fitting coefficients and standard deviations determined.Additionally,the Prigogine-Flory-Patterson(PFP)theory and the Extended Real Associated Solution(ERAS)model were employed to correlate the excess molar volume,while the Perturbed Chain Statistical Associating Fluid Theory(PC-SAFT)was used to predict the density of mixtures.
基金supported by the National Natural Science Foundation of China(Grant Nos.12473001,11975072,11875102,11835009,and 11965013)the National SKA Program of China(Grant Nos.2022SKA0110200 and 2022SKA0110203)+1 种基金the National 111 Project(Grant No.B16009)supported by Yunnan High-level Talent Training Support Plan Young&Elite Talents Project(Grant No.YNWR-QNBJ-2018-181).
文摘The comprehension of universal thermodynamic behaviors in the supercritical region is crucial for examining the characteristics of black hole systems under high temperature and pressure.This study is devoted to the analysis of characteristic lines and crossover behaviors within the supercritical region.By making use of the free energy,we introduce three key thermodynamic quantities:scaled variance,skewness,and kurtosis.Our results demonstrate that the Widom line,associated with the maximal scaled variance,can effectively differentiate between small and large black hole-like subphases,each displaying distinct thermodynamic behaviors within the supercritical region.Furthermore,by utilizing quasinormal modes,we identify the Frenkel line,offering a dynamic perspective to distinguish between small and large black hole-like subphases.These contribute to a deeper comprehension of black hole subphases in the supercritical region,thus illuminating new facets of black hole thermodynamics.
基金financial support by the Phosphogypsum Low-Temperature Decomposition to Produce Calcium-Based Materials and Sulfuric Acid Raw Gas Technology(Horizontal Project)(8503009049)National Natural Science Foundation of China(52376101).
文摘The thermal effects,spontaneity and proceeding degree of 32 chemical reactions during coal reductive decomposition phosphogypsum(PG)to prepare CaO and SO_(2)are analyzed utilizing thermodynamic theory and method.The ideal reaction temperature for PG decomposition and desulfurization is 1173-1273 K.The 10 key chemical reactions controlling coal reductive decomposition PG have been selected.The heat release of critical exothermic reactions can satisfy the autothermal operation of PG decomposition and desulfurization process.Meanwhile,the spontaneity of oxidation reactions has thermodynamically priority over reduction reactions.But the reaction mechanism shows that the oxidation of CaS by O_(2)is in parallel competition with the reduction of CaSO_(4)by CO and C.Furthermore,clarifying the regulatory mechanisms of PG decomposition temperature and reaction atmosphere(reducibility and oxidation)is beneficial for maximizing the production of CaO and SO_(2).
基金supported by the Program of the National Natural Science Foundation of China(Grant No.52371055)the Young Elite Scientist Sponsorship Program Cast(Grant No.YESS20200139)+1 种基金the Basic Scientific Research Project of Liaoning Provincial Department of Education(Grant No.JYTMS20230618)Special thanks are due to the instrumental analysis from the Analytical and Testing Centre,Northeastern University.
文摘A principle was proposed for designing a method to seal anodized aluminum used in semiconductor processing apparatuses.Thermodynamic calculations and Fick’s second law were used to reveal trends in the metal ion deposition,deposition product stability,vapor pressures of halides for selected metal ions,the holding temperature,and time.Interactions between ion concentrations and the sealing temperature were also revealed.According to the design principles,anodized aluminum dipped in 1 mM Cr^(3+)ion solution and steam-sealed for 18 h exhibited the highest corrosion resistance when exposed to 5 wt.%HCl solution and HCl gas,verifying the designed results.
基金financial support by the National Key Research and Development Program of China(No.2023YFB3809101)the National Natural Science Foundation of China(Nos.52371010 and 52422407)+1 种基金the Science and Technology Committee of Shanghai,China(No.21ZR1423600)the Open Project of State Key Laboratory of Baiyunobo Rare Earth Resources Researches and Comprehensive Utilization,China.
文摘Mg-Zn-Mn alloys have the advantages of low cost,excellent mechanical properties,and high corrosion resistance.To clarify the phase equilibria of Mg-Zn-Mn alloy in the Mg-rich corners,the present work experimentally investigated the phase equilibria in the Mg-rich corner at 300-400°C with equilibrated alloy method using electron probe micro analyzer(EPMA),X-ray diffractometer(XRD),transmission electron microscopy(TEM),and differential scanning calorimeter(DSC).Mn atoms were found to dissolve into MgZn_(2) to form a ternary solid-solution type compound,in which Mn content can be up to 15.1at%at 400°C.Three-phase equilibrium ofα-Mg+MgZn_(2)+α-Mn and liquid+α-Mg+MgZn_(2) were confirmed at 400°C.Subsequently,thermodynamic modeling of the Mg-Zn-Mn system was carried out using the CALPHAD method based on the experimental data of this work and literature data.The calculated invariant reaction Liquid+α-Mn→α-Mg+MgZn_(2) at 430°C shows good agreement with the DSC results.In addition,the results of solidification path calculations explain the microstructure in the ascast and annealed alloys well.The agreement between the calculated results and experimental data proves the self-consistency of the thermodynamic database,which can provide guidance for the compositional design of Mg-Zn-Mn alloys.
