Properties Of Liquid Metals Research Articles

Static and dynamic properties of liquid Zn, Cd and Hg divalent metals: An orbital free ab initio molecular dynamics study

We report a study on several static and dynamic properties of liquid Zn, Cd, and Hg divalent metals at thermodynamic conditions near their respective triple points. The calculations have been carried out by using the orbital free ab initio molecular dynamics (OF-AIMD) simulation technique which is based on the density functional theory. Results are reported for a range of static structural magnitudes, such as static structure factors, pair distribution functions and coordination numbers. A comparison with the available X-ray diffraction data shows that the OF-AIMD method can provide a reasonable description of the static structure. As for the dynamic properties, results are reported for both single and collective dynamics. The calculated dynamic structure factors show side peaks which point to the existence of collective density excitations. Finally, we report the calculation of some transport coefficients which are compared with the corresponding experimental data. Comparison with other AIMD methods show some discrepancies in dynamic properties, and possible modifications of the approach used in this study are suggested accordingly.

Surface tension measurement of liquid metal with inelastic light-scattering spectroscopy of a thermally excited capillary wave

Thermally excited capillary waves propagate everywhere on a liquid surface. The relationship between the frequency and wavelength of the capillary wave reflects the surface tension of the liquid, and the lifetime of the capillary wave reflects the shear viscosity of the liquid. By observing a capillary wave with inelastic light-scattering spectroscopy, we can obtain the surface tension and the viscosity from the frequency modulation of the light and the spectral width of the scattered light. In this study, we observed capillary waves on liquid metal using high-resolution spectroscopy, and successfully measured their properties in a non-contact manner. In the experiment, values were obtained at a frequency of about 20 kHz. The values were equivalent to those at 0 Hz, since the properties of liquid metals are constant at least in the frequency region from 0 to several tens of kilohertz.

Dissolution of solid copper in liquid tin enhanced by the liquid structural transition

Physicochemical properties of liquid metals have great impact on many technological processes. Anomalies in liquid structure of metals are affected by temperature at constant pressure. This study investigated the dissolution kinetics of solid Cu in liquid Sn under the influence of structural transition of liquid Sn at temperatures varying from 673 K to 823 K. Structural transition significantly affected the dissolution rate constant of solid Cu. Correspondingly, application of liquid structural transition significantly decreased the activation energy of dissolution and the apparent activation energy of diffusion.

Breakup behavior of a molten metal jet

The breakup behavior of a molten metal jet into a still gas was studied numerically. Droplet formation was modeled by imposing a sinusoidal waveform perturbation or an amplitude-modulated waveform perturbation. The effect of the temperature on the jet breakup behavior was examined by modeling the liquid metal properties, including density, viscosity, and surface tension, as a function of the temperature. The process by which a molten metal jet was ejected from an orifice exit was modeled to include the wetting of the molten metal on the orifice surface at the gas interface using a dynamic contact angle (θD). The effects of the oscillation amplitude (A=0.10–0.30), the Strouhal number (St=0.20–0.50) and the Weber number (We=11.63–129.19) were studied. The imposition of a periodic perturbation yielded linear or nonlinear breakup behavior in the molten metal jet. The conditions found to be optimal for the continuous generation of uniform droplets were identified by optimizing the uniformity of the main droplet, the regular distance between main droplets, the presence of satellite droplets, and the coalescence of the droplets due to surface instabilities and hydrodynamic interactions. The effects of the modulated amplitude (B) and the frequency ratio (N) on the coalescence and separation of neighboring droplets were examined.

Empirical model for the estimation of thermophysical properties of liquid metal alloys

A model for calculating the main properties of liquid metal binary alloys at standard pressure based on experimental data observation is presented. Given the characteristics of the pure metals, the model allows to calculate density, surface tension, electrical resistivity and thermal conductivity of binary alloys at various concentrations along the liquidus line. Some preliminary comparisons for Al-Si and Al-Cu systems are in satisfactory agreement with the model.

Equation of state and artificial neural network to predict the thermodynamic properties of pure and mixture of liquid alkali metals

A statistical mechanical equation of state is developed to predict the volumetric properties of pure and mixture liquid alkali metals at different temperatures, pressures and compositions. The temperature dependent parameters of the equation of state have been calculated using corresponding states correlation based on the normal boiling point parameters as scaling constants. It is shown that the knowledge of just normal boiling point and its liquid density are sufficient to estimate the thermodynamic properties of pure and mixture liquid alkali metals in different conditions. Besides, the performance of artificial neural network (ANN) based on back propagation training with 10 neurons in hidden layer for prediction of behavior of presented systems was investigated. A collection of 512 data points for above systems in different temperatures and pressures was used. The Tao–Mason equation of state (TM EOS) and ANN model results have good agreement with the experimental data with absolute average deviations of 0.74% and 0.299%, respectively.

Magnetic Properties of Liquid 3d Transition Metal–Au Alloys

In the present study, the magnetic properties of liquid transition metal–Au alloys were investigated as a function of temperature and composition. The magnetic susceptibility χ of liquid Ti–Au and V–Au alloys was found to be almost independent of temperature or to have only a weak positive temperature dependence, which suggests that the Ti and V ions in the alloys are formally in the nonmagnetic state. For Au-rich compositions, χ in the nonmagnetic state was analyzed using the Anderson model. Liquid Cr1−cAuc with 0.5 ≤ c and Mn1−cAuc with 0.3 ≤ c obeyed the Curie–Weiss law with regard to the dependence of their χ on temperature. It is interesting to note that the composition dependences of the χ values of liquid Cr–Au, Mn–Au, and Fe–Au alloys have maxima at compositions of 50 at. % Cr, 70 at. % Mn, and 85 at. % Fe, respectively. The magnetic susceptibilities of liquid Fe–Au, Co–Au, and Ni–Au alloys obtained in this work also exhibited Curie–Weiss behavior with reasonable values for the effective numbers o...

Nanosized Nucleus-Supercooled Liquid Interfacial Free Energy and Thermophysical Properties of Early and Late Transition Liquid Metals

Crystal–liquid interfacial free energy is important to understand in crystal study, for example, nucleation, crystal growth, and vitrification. Here, we report the nanosized nucleus-supercooled liquid interfacial free energy of early and late transition liquid metals using the electrostatic levitation (ESL) technique and classical homogeneous nucleation theory (CNT). For the estimation of the interfacial free energy, we obtained thermophysical parameters of the transition liquid metals (Ti, Fe, Ni, Zr, Nb, Rh, and Hf), such as hypercooling limit (ΔThyp), specific heat (Cp), total hemispherical emissivity (eT), and density (ρ). The estimated interfacial free energies of Ti, Ni, and Zr agreed well with a previous report having similar hypercooling limit and fusion enthalpy, while Fe, Nb, Rh, and Hf show different values from the report. This reflects the importance of accurate measurement of the two quantities. The obtained Turnbull’s coefficients (α) of the liquid metals is higher than 0.45. The interfacia...

Density measurements and structural properties of liquid and amorphous metals under high pressure

We have implemented an in situ X-ray diffraction analysis method suitable for the determination of pressure–volume–temperature equations of state in the critical case of liquid and amorphous materials over an extended thermodynamic range (T>2000 K and P>40 GPa). This method is versatile, it can be applied to data obtained using various angle-dispersive X-ray diffraction high pressure apparatus and, contrary to in situ X-ray absorption techniques, is independent from the sample geometry. Further advantage is the fast data acquisition (between 10 and 300 s integration time). Information on macroscopic bulk properties (density) and local atomic arrangement (pair distribution function g(r)) can be gathered in parallel. To illustrate the method, we present studies on liquid Fe–S alloys in the Paris Edinburgh press and in laser-heated diamond anvil cell (DAC), and measurements on Ce glass in DAC at room temperature.

Liquid metal as energy transportation medium or coolant under harsh environment with temperature below zero centigrade

The current highly integrated electronics and energy systems are raising a growing demand for more sophisticated thermal management in harsh environments such as in space or some other cryogenic environment. Recently, it was found that room temperature liquid metals (RTLM) such as gallium or its alloys could significantly reduce the electronics temperature compared with the conventional coolant, like water, oil or more organic fluid. However, most of the works were focused on RTLM which may subject to freeze under low temperature. So far, a systematic interpretation on the preparation and thermal properties of liquid metals under low temperature (here defined as lower than 0°C) has not yet been available and related applications in cryogenic field have been scarce. In this paper, to promote the research along this important direction and to overcome the deficiency of RTLM, a comprehensive evaluation was proposed on the concept of liquid metal with a low melting point below zero centigrade, such as mercury, alkali metal and more additional alloy candidates. With many unique virtues, such liquid metal coolants are expected to open a new technical frontier for heat transfer enhancement, especially in low temperature engineering. Some innovative ways for making low melting temperature liquid metal were outlined to provide a clear theoretical guideline and perform further experiments to discover new materials. Further, a few promising applied situations where low melting temperature liquid metals could play irreplaceable roles were detailed. Finally, some main factors for optimization of low temperature coolant were summarized. Overall, with their evident merits to meet various critical requirements in modern advanced energy and power industries, liquid metals with a low melting temperature below zero centigrade are expected to be the next-generation high-performance heat transfer medium in thermal managements, especially in harsh environment in space.

Temperature Dependent Surface Properties of Liquid Alkali Metals

Temperature dependent surface properties like surface tension (γ) and surface entropy (SV) of liquid alkali metals are studied in the present paper. Our newly constructed parameter free model potential is used to describe the electron-ion interaction. To see the influence of local field correction function on surface properties of liquid alkali metal, we have used Sarkar et al local field correction function. The present results are found in good agreement with available experimental data as well as other theoretical data. Lastly we conclude that our model potential is capable to explain surface properties of liquid alkali metals.

Method for obtaining ingots of the A34 solder based on an investigation into the relation between the structure and properties of liquid and solid metals

A comparative analysis of the influence of the modifying method on the structure and phase composition of the ingots of the A34 solder is performed. Modification is performed by force of heating the melt to 1000°C and introducing the fine-crystalline remelt in an amount of 5% of the charge amount into the melt. The investigation is performed using DTA and metallographic analysis. The structure of the ingot of the A34 solder is additionally investigated at elevated temperatures (150 and 300°C) by the sc-AFM method using the NTEGRA Therma probe nanolaboratory, and recommendations are given to optimize the modes of casting and thermal treatment.

Atomic Transport Properties of 3D Liquid Transition Metals Using Different Reference Systems

Atomic transport properties like self diffusion coefficient (D), viscosity coefficient (η) of 3d liquid transition metals are studied. Here we have applied our own model potential to describe electron ion interaction with different reference system like Percus - Yevick Hard Sphere (PYHS), One Component Plasma (OCP) and Charge Hard Sphere (CHS) systems. We have investigated the effect of different correction function like Hartree (H), Vashishta-Singwi (VS), Hubbard-Sham (HS), Sarkar et al (S), Ichimaru-Utsumi(IU), Taylor (T) and Farid et al (F) on atomic transport properties. The proper choice of the model potential alongwith the local field correction function and reference system plays a vital role in the study of the atomic transport properties of 3d liquid transition metals.

Calculation of thermodynamic properties of liquid alkali metals by the first-principle-pseudopotential and Weeks-Chandler-Andersen methods

339 The methods of thermodynamic perturbation the� ory (TPT) combined with the effective ionpair inter� action considered within the framework of the nearly� freeelectron approximation based on the pseudopo� tential approach have actively been used for calculat� ing the thermodynamic properties of metal melts for many years (1-8). In this case, if model pseudo� potentials were used for these purposes in combination with various TPT methods (variational (1-6), Weeks- Chandler-Andersen (9) (WCA) (1, 2, 6, 7), and Barker-Henderson (2)), the firstprinciple ones were used only with the variational methods (3, 4, 8). In this study, together with the WCA method, we used the firstprinciple pseudopotential method (10) previously proposed by us, which enables us to con� sider a very wide circle of properties and gives good quantitative and qualitative results for simple metals and their alloys in the solid state (11). In this case, both the energy functions and their first and second deriva� tives agree well with the experimental data. Recently, this pseudopotential was used for calculating the thermodynamic properties of liquid alkali metals within the framework of the variational method (8). The Schrodinger pseudowave equation for con� duction electrons has the form ,( 1) where Hps and φk are called the pseudoHamiltonian acting on conduction electrons and their pseudowave functions, respectively; k is the conductionelectron state, is the pseudopotential acting on the elec� tron state k, and K is the kineticenergy operator. The transformation of the true Schrodinger equation into the pseudowave equation is exact, and the eigenval�

Atomistic molecular point of view for liquid lead and lithium in Nuclear Fusion technology

Understanding the behavior and properties of liquid metals is a crucial milestone in different current Nuclear Technology developments. Extracting both structural and dynamical properties of liquid metals via Molecular Dynamics simulations, represents a strong pillar for multiscale modeling efforts aiming to understand the suitability of these compounds. Here we present first results on the validation of two semi-empirical potentials for Li and Pb in liquid phase. Our results establish a solid base as a previous, but crucial step, to implement a LiPb cross potential. Structural and thermodynamical analyses confirm that the analyzed potentials for Li and Pb are sufficiently accurate to simulate both elements in the liquid phase, and in conditions of interest for Nuclear Technology.

Research on Flow Field of Double-Nozzles Bottom Blowing CAS Process with Properties of Liquid Metal through Numerical Simulation

The Fluid Flow of Liquid Metal in Ladles of CAS-OB Refining Process Is a Complicated Turbulent Transmission Process. it Behaves much More Complicated than in Traditional Ladle because of Immersion Snorkel. this Paper Describes Properties of Liquid Metal Based on Full Buoyancy Model. the Author Analyzes the Characteristics of Flow Field in Single and Double-nozzles Bottom Blowing Condition through Numerical Simulation Method. Double-nozzles Bottom Blowing Could Improve Blending Effect in the Region where Is Weak Mixing. this Paper Also Draws an Empirical Formula which Tells how Gas Blowing and Immersion Depth Influence Mixing Time in CAS-OB Ladle through Dimensionless Analysis.

Theoretical Investigation of Thermodynamical and Structural Properties of 3d Liquid Transition Metals Using Different Reference Systems

The present paper deals with the theoretical investigation of thermodynamical and structural properties like internal energy (E), entropy (S), Helmholtz free energy (F), isothermal compressibility (χT), specific Heat (CV), structure factor S(q), and long wave length limit S(0) of structure factor of 3d liquid transition metals. To describe electron-ion interaction we have used our newly constructed parameter free model potential. To perform this task, we have used different reference systems like Percus Yevick Hard Sphere (PYHS), One Component Plasma (OCP), and Charged Hard Sphere (CHS) reference systems. We have also seen the influence of different local field correction functions like Hartree (HR), Taylor (TR), and Sarkar et al. (SR) on thermodynamical properties of 3d liquid transition metals. Finally we conclude that the proper choice of the model potential along with reference system plays a vital role in the study of thermodynamical and structural properties of 3d liquid transition metals.

Magnetic Property of Liquid 3d Transition Metal–Sb Alloys

Magnetic Property of Liquid 3d Transition Metal–Sb Alloys

Eutectic Liquid Alloys for Plasmonics: Theory and Experiment

We report a method based on density functional theory molecular dynamics that allows us to calculate the plasmonic properties of liquid metals and metal alloys from first principles with no a priori knowledge of the system. We show exceptional agreement between the simulated and measured optical constants of liquid Ga and the room temperature liquid In-Ga eutectic alloy (T(m) = 289 K). We then use this method to analyze the plasmonic properties of various alloy concentrations in the In-Ga system. The plasmonic performance of the In-Ga system decreases with increasing In concentration. However, the benefits of a room-temperature plasmonic liquid are likely to outweigh the minor reduction in plasmonic performance when moving from pure Ga to the eutectic composition. Our results show that density functional theory molecular dynamics can be used as a predictive tool for studying the optical properties of liquid metal systems amenable to plasmonics.

A new regularity and an equation of state for alkali metals over the whole liquid range

In this paper, we have derived an equation of state (EoS) for liquid alkali metals based on a suggested potential function over the whole liquid range including metal–nonmetal transition. This EoS is based on the interaction of nearest neighbors according to the characteristics of the soft repulsive interaction in dense and large attractive interaction in expanded liquid alkali metals. PVT data of dense liquid alkali metals obey the equation (2Z−1)Vm=A+Bρ over the whole range of liquid densities, where Z, Vm, and ρ are compression factor, molar volume, and molar density, respectively. The intercept A and slope B of this equation are related to the attractive and repulsive parts of suggested potential function, respectively, and both depend on temperature. The new EoS has been used to calculate the molar density and other thermodynamic properties such as isobaric expansion coefficient, αP; isothermal compressibility, κT; and internal pressure, Pi; of liquid alkali metals at any temperature and pressure over the whole liquid range. The results show good agreement between the values obtained using this equation and the experimental and literature data. To show the ability of this EoS in prediction of thermodynamic properties of liquid alkali metals over the whole liquid range, the results have been compared with some other equations.