In this work,a novel computational framework for establishment of atomic mobility database directly from the experimental composition profiles and its uncertainty quantification was developed by merging the Bayesian i...In this work,a novel computational framework for establishment of atomic mobility database directly from the experimental composition profiles and its uncertainty quantification was developed by merging the Bayesian inference with the Markov chain Monte Carlo algorithm into the latest version of the Hit DIC software.By treating the simulation of composition profiles with the composition-dependent coefficients as the forward problem,the inverse coefficient problem that provides the potential way to compute the atomic mobilities directly from composition profiles can be postulated.The values and uncertainties of the atomic mobility parameters of interest were assessed by means of Bayesian inference,where the composition profiles were consumed directly.Benchmark tests that consider the number of diffusion couples and the noise levels were conducted.Practical application of the current framework in determination of atomic mobility descriptions of fcc Ni-Ta and Ni-Al-Ta alloys was performed.Further discussion about the results of the benchmark tests and practical study case indicated that the present computational framework together with numbers of composition profiles from the multiple diffusion couples can help to establish the high-quality atomic mobility database of the target multicomponent alloys.展开更多
As potential cast and wrought Mg alloys,Mg-X(X=Al,Zn,Sn)based alloys have attracted great interest.This work is to develop a dataset of atomic mobilities that is valid over a wide composition range.With the obtained m...As potential cast and wrought Mg alloys,Mg-X(X=Al,Zn,Sn)based alloys have attracted great interest.This work is to develop a dataset of atomic mobilities that is valid over a wide composition range.With the obtained mobilities,and a compatible thermodynamic description,as well as thermophysical parameters,simulations are performed to predict the characteristics of precipitation evolution.Examples are presented for the isothermal aging processes in Mg-x wt.%Al(x=5.9,6,8.8,9),Mg-x wt.%Zn(x=6,6.2,8,8.65),Mg-x wt.%Sn(x=6.04,6.92,8.64)alloys.The simulated size distribution,number density and volume fraction of precipitates reasonably account for the experimental results and provide additional information for further alloy composition design and heat treatment optimization.展开更多
To have a better understand on the change of microstructure via kinetics, the diffusion behavior of Mg alloys is of special interest to researchers. Meanwhile, diffusion coefficients of Mg based alloys can explain and...To have a better understand on the change of microstructure via kinetics, the diffusion behavior of Mg alloys is of special interest to researchers. Meanwhile, diffusion coefficients of Mg based alloys can explain and represent their diffusion behavior well. The evolution of experimental and calculated methods for detecting and extracting diffusion coefficients was discussed briefly. The reasonable diffusion data, especially self-diffusion coefficients, impurity diffusion coefficients and inter-diffusion coefficients of Mg alloys, were reviewed in detail serving to design the Mg alloys with higher accuracy. Then the practical applications of diffusion coefficients of Mg alloys were summarized,including diffusional mobility establishing, precipitation simulation and mechanical properties prediction.展开更多
A variety of experimental tracer diffusivities of Mg and O in magnesium oxide available in the literature were first assessed.Atomic mobilities including bulk and short-circuit diffusion of Mg and O were then obtained...A variety of experimental tracer diffusivities of Mg and O in magnesium oxide available in the literature were first assessed.Atomic mobilities including bulk and short-circuit diffusion of Mg and O were then obtained by means of the CALPHAD(Calculation of Phase Diagram)approach.Afterwards,the diffusion-controlled kinetic model of oxidation in a gas-MgO-Mg environment was developed based on the moving boundary model and Fick's law,coupling with the modified thermodynamic description of MgO.A mathematical expression for parabolic rate constant kp of the oxide scale was derived for magnesia and correlated with the thermodynamic and diffusion kinetic information.The evaluated kp results were in line with the experimental data.Finally,the oxidation process of pure magnesium at 673 K was model-predicted,and the predicted evolution of the oxide thicknesses agreed very well with the experimental data.It was indicated that the grain boundaries diffusion of magnesium cations predominated the high temperature oxidation process.展开更多
This paper presents original research studying the effects of biocompatible nanoparticles standardized(ICNB)on the permeability of erythrocytes and eryptosis.The presented evidence demonstrates that changing orientati...This paper presents original research studying the effects of biocompatible nanoparticles standardized(ICNB)on the permeability of erythrocytes and eryptosis.The presented evidence demonstrates that changing orientation and mobility protons of the hydrogen atoms in the pericellular fluid significantly modifies the permeability and physiological activity of erythrocytes.The leading role of the state of cell membrane and transport activity enzymes(ATPase)in ensuring its permeability and functional activity is exaggerated.Magnetite nanoparticles(ICNB)act on the fluid of pericellular structure by changing the orientation and mobility of hydrogen protons that ultimately determine the permeability,and physiological activity of cells.These studies support the G.Ling's theory of an"association-induction"and"multi-layered organization polarized water".展开更多
Knowledge of diffusivity is a prerequisite for understanding many scientific and technological disciplines. In this paper, firstly major experimental methods, which are employed to provide various diffusivity data, ar...Knowledge of diffusivity is a prerequisite for understanding many scientific and technological disciplines. In this paper, firstly major experimental methods, which are employed to provide various diffusivity data, are briefly described. Secondly, the fun-damentals of various computational methods, including first-principles method, embedded atomic method/molecular dynamic simulation, semi-empirical approaches, and phenomenological DICTRA technique, are demonstrated. Diffusion models re- cently developed for order/disorder transitions and stoichiometric compounds are also briefly depicted. Thirdly, a newly estab- lished diffusivity database for liquid, fcc_A1, Lie, bcc_A2, bcc_B2, and interrnetallic phases in the multicomponent A1 alloys is presented via a few case studies in binary, ternary and quaternary systems. And the integration of various computational techniques and experimental methods is highlighted. The reliability of this diffusivity database is validated by comparing the calculated and measured concentration profiles, diffusion paths, and Kirkendall shifts in various binary, ternary and quaternary diffusion couples. Next, the established diffusivity databases along with thermodynamic and other thermo-physical properties are utilized to simulate the microstructural evolution for Al alloys during solidification, interdiffusion and precipitation. A spe- cial discussion is presented on the phase-field simulation of interdiffusion microstructures in a series of Ni-Al diffusion couples composed of γ, γ＇, and β phases under the effects of both coherent strain and external compressive force. Future orientations in the establishment of next generation of diffusivity database are finally addressed.展开更多
基金financially supported by the National Key Research and Development Program of China(No.2016YFB0301101)the Hunan Provincial Science and Technology Program of China(No.2017RS3002)-Huxiang Youth Talent Plan+1 种基金the Youth Talent Project of Innovation-driven Plan at Central South University(No.2019XZ027)the support from the Fundamental Research Funds for the Central Universities of Central South University(No.2018zzts129)。
文摘In this work,a novel computational framework for establishment of atomic mobility database directly from the experimental composition profiles and its uncertainty quantification was developed by merging the Bayesian inference with the Markov chain Monte Carlo algorithm into the latest version of the Hit DIC software.By treating the simulation of composition profiles with the composition-dependent coefficients as the forward problem,the inverse coefficient problem that provides the potential way to compute the atomic mobilities directly from composition profiles can be postulated.The values and uncertainties of the atomic mobility parameters of interest were assessed by means of Bayesian inference,where the composition profiles were consumed directly.Benchmark tests that consider the number of diffusion couples and the noise levels were conducted.Practical application of the current framework in determination of atomic mobility descriptions of fcc Ni-Ta and Ni-Al-Ta alloys was performed.Further discussion about the results of the benchmark tests and practical study case indicated that the present computational framework together with numbers of composition profiles from the multiple diffusion couples can help to establish the high-quality atomic mobility database of the target multicomponent alloys.
基金financially supported by the National Key Research and Development Program of China(No.2016YFB0701202)the Innovation Foundation for Postgraduate and Fundamental Research Funds of Central South University(No.1053320182102)China Scholarship Council(No.201906370116)for the award of a fellowship and funding。
文摘As potential cast and wrought Mg alloys,Mg-X(X=Al,Zn,Sn)based alloys have attracted great interest.This work is to develop a dataset of atomic mobilities that is valid over a wide composition range.With the obtained mobilities,and a compatible thermodynamic description,as well as thermophysical parameters,simulations are performed to predict the characteristics of precipitation evolution.Examples are presented for the isothermal aging processes in Mg-x wt.%Al(x=5.9,6,8.8,9),Mg-x wt.%Zn(x=6,6.2,8,8.65),Mg-x wt.%Sn(x=6.04,6.92,8.64)alloys.The simulated size distribution,number density and volume fraction of precipitates reasonably account for the experimental results and provide additional information for further alloy composition design and heat treatment optimization.
基金financially supported by the China Scholarship Council (Grant No: 202006890008), ChinaScience and Technology Committee of Shanghai (19010500400)+1 种基金the “111” project (D16002)the Independent Research Project of State Key Laboratory of Mechanical Transmissions (Grant No. SKLMT-ZZKT-2021M11)。
文摘To have a better understand on the change of microstructure via kinetics, the diffusion behavior of Mg alloys is of special interest to researchers. Meanwhile, diffusion coefficients of Mg based alloys can explain and represent their diffusion behavior well. The evolution of experimental and calculated methods for detecting and extracting diffusion coefficients was discussed briefly. The reasonable diffusion data, especially self-diffusion coefficients, impurity diffusion coefficients and inter-diffusion coefficients of Mg alloys, were reviewed in detail serving to design the Mg alloys with higher accuracy. Then the practical applications of diffusion coefficients of Mg alloys were summarized,including diffusional mobility establishing, precipitation simulation and mechanical properties prediction.
文摘A variety of experimental tracer diffusivities of Mg and O in magnesium oxide available in the literature were first assessed.Atomic mobilities including bulk and short-circuit diffusion of Mg and O were then obtained by means of the CALPHAD(Calculation of Phase Diagram)approach.Afterwards,the diffusion-controlled kinetic model of oxidation in a gas-MgO-Mg environment was developed based on the moving boundary model and Fick's law,coupling with the modified thermodynamic description of MgO.A mathematical expression for parabolic rate constant kp of the oxide scale was derived for magnesia and correlated with the thermodynamic and diffusion kinetic information.The evaluated kp results were in line with the experimental data.Finally,the oxidation process of pure magnesium at 673 K was model-predicted,and the predicted evolution of the oxide thicknesses agreed very well with the experimental data.It was indicated that the grain boundaries diffusion of magnesium cations predominated the high temperature oxidation process.
文摘This paper presents original research studying the effects of biocompatible nanoparticles standardized(ICNB)on the permeability of erythrocytes and eryptosis.The presented evidence demonstrates that changing orientation and mobility protons of the hydrogen atoms in the pericellular fluid significantly modifies the permeability and physiological activity of erythrocytes.The leading role of the state of cell membrane and transport activity enzymes(ATPase)in ensuring its permeability and functional activity is exaggerated.Magnetite nanoparticles(ICNB)act on the fluid of pericellular structure by changing the orientation and mobility of hydrogen protons that ultimately determine the permeability,and physiological activity of cells.These studies support the G.Ling's theory of an"association-induction"and"multi-layered organization polarized water".
基金supported by the National Basic Research Program of China (Grant No. 2011CB610401)the Creative Research Group of the National Natural Science Foundation of China (Grant No. 51021063)+1 种基金the National Natural Science Foundation of China (Grant No. 50831007)the Science Center for Phase Diagrams & Materials Design and Manu-facture, Central South University
文摘Knowledge of diffusivity is a prerequisite for understanding many scientific and technological disciplines. In this paper, firstly major experimental methods, which are employed to provide various diffusivity data, are briefly described. Secondly, the fun-damentals of various computational methods, including first-principles method, embedded atomic method/molecular dynamic simulation, semi-empirical approaches, and phenomenological DICTRA technique, are demonstrated. Diffusion models re- cently developed for order/disorder transitions and stoichiometric compounds are also briefly depicted. Thirdly, a newly estab- lished diffusivity database for liquid, fcc_A1, Lie, bcc_A2, bcc_B2, and interrnetallic phases in the multicomponent A1 alloys is presented via a few case studies in binary, ternary and quaternary systems. And the integration of various computational techniques and experimental methods is highlighted. The reliability of this diffusivity database is validated by comparing the calculated and measured concentration profiles, diffusion paths, and Kirkendall shifts in various binary, ternary and quaternary diffusion couples. Next, the established diffusivity databases along with thermodynamic and other thermo-physical properties are utilized to simulate the microstructural evolution for Al alloys during solidification, interdiffusion and precipitation. A spe- cial discussion is presented on the phase-field simulation of interdiffusion microstructures in a series of Ni-Al diffusion couples composed of γ, γ＇, and β phases under the effects of both coherent strain and external compressive force. Future orientations in the establishment of next generation of diffusivity database are finally addressed.
