Born-Mayer Potential Research Articles

Elastic properties of TiC and TiN crystals in high temperature range

The elastic properties of crystals at high temperature are of significant interest as they affect the mechanical stability and performance of materials at elevated temperatures. In present study a theory for evaluating the temperature variation of second third and fourth order elastic constants for face centred cubic crystal structure solids is used on the basis of Coulomb and Born-Mayer potential using nearest-neighbour distance and hardness parameter. The theory is first applied to get the second order elastic constants (SOECs) and third order elastic contants (TOECs) for TiC and TiN crystals at different temperatures up to 500 K. In addition, the elastic constants thus obtained are used to evaluate the first order pressure derivatives (FOPDs) SOECs and TOECs. The elastic properties of these crystals at high temperature are of significant interest and are related to other important material properties such as thermal expansion, thermal conductivity, phase transformations, creep behaviour, oxidation resistance, and high-temperature strength.The results obtained show that the second order elastic constants and third order elastic constants of TiC are highest, so mechanical properties of TiC will be better than TiN, which makes it stiffer and more resistant to deformation under an applied load. These properties make TiC a popular material for cutting tools, wear-resistant coatings, and other high-performance applications.

Applying the Born-Mayer model to describe the physicochemical properties of FLiNaK ternary melt

In this study, the Born-Mayer potential was used to calculate the physicochemical properties of the FLiNaK ternary eutectic. The commonly used Fumi and Tosi parameters were here superseded by those obtained ab initio to push the model accuracy closer to its suppositional limit. Density, local structure data, self-diffusion coefficients, viscosity, thermal conductivity and heat capacity were calculated. Comparison with reference data, both theoretical and experimental, reveals the performance of the Born-Mayer potential for obtaining the properties of the FLiNaK. In addition, new data on the local structure dynamics is presented by the calculation of the ion pair lifetimes.

Molecular Dynamics Simulation of Thermophysical Properties and the Microstructure of Na2CO3 Heat Storage Materials

In recent years, heat storage technology has attracted wide attention in the fields of renewable energy storage for its relatively high melting point, high heat storage capacity and economy, Na2CO3 and eutectic salt mixtures containing Na2CO3 are promising candidates in the field of solar energy storage. In this paper, a molecular dynamics (MD) simulation of Na2CO3 was conducted with the Born–Mayer potential function. The simulated solid–liquid phase change temperature is 1200 K, and the error is 5.4%. The heat capacity at constant pressure (Cp) is higher in liquid than in solid, the average Cp of solid is 1.45 J/g and that of liquid is 1.79 J/g, and the minimum error is 2.8%. The simulation results revealed the change rules of density and thermal expansion coefficient of Na2CO3 in the process of heating up, and these changes were analyzed by radial distribution functions (RDF) and angular distribution functions (ADF). Moreover, the RDF and ADF results show that the atomic spacing of Na2CO3 increases, the coordination number decreases, and the angle distribution between atoms becomes wider as the temperature rises. Finally, this paper examined the microscopic changes of ions during the phase transition of Na2CO3 from solid to liquid. It is concluded that the angle change of CO32− in the liquid state is more sharply. This study improves the understanding of the thermodynamic properties and local structure of Na2CO3 and provides theoretical support for Na2CO3 heat storage materials.

Investigation of the Effect of Temperature on Ultrasonic, Mechanical and Thermal Properties in Single Silver Nanowire

The present paper reports the elastic, mechanical and thermophysical properties of silver nanowire (Ag NW) using ultrasonic techniques at temperature dependent. Higher order elastic constants are calculated using Coulomb and Born-Mayer potential up to second nearest neighbour. To compute mechanical parameters such as young modulus, bulk modulus, shear modulus tetragonal modulus, Poisson's ratio, fracture to toughness ratio and Zener anisotropy factor for finding imminent performance of the single silver nanowire at temperature dependent using second order elastic constants. The Ag NW is found to be brittle in nature at room temperature. Finally, we have evaluated the ultrasonic velocities, ultrasonic attenuation due to phonon–phonon interaction and thermoelastic relaxation for longitudinal wave and shear waves along <100>, <110> and <111> crystallographic directions in the temperature range 100-300K of silver nanowire using the higher order elastic constants. The attained results are discussed in correlation with available outcomes on these properties for the silver nanowire.

Mechanical and thermophysical properties of 4d-transition metal mononitrides

Abstract The second and third order elastic constants (SOECs and TOECs) of 4d-transition metal mononitrides XN (X: Zr and Nb) have been computed in the temperature range 0 K–500 K using Coulomb and Born–Mayer potential up to second nearest neighbours. In order to investigate the mechanical stability of XN, the computed values of SOECs have been utilized to find out Young’s modulus, bulk modulus, shear modulus, Zener anisotropy and Poisson’s ratio. Furthermore, the SOECs are applied to compute the wave velocities for shear and longitudinal modes of propagation along ⟨100⟩, ⟨110⟩ and ⟨111⟩ crystallographic orientations in the temperature range 100 K–500 K. Temperature dependent Debye average velocity, ultrasonic Grüneisen parameters (UGPs) and Debye temperature have been evaluated. In present work the thermal conductivity of chosen materials has also been evaluated using Morelli-Slack’s approach. Specific heat and total internal thermal energy have been calculated in the temperature range 100 K–500 K on the basis of Debye theory. Thermal relaxation time, acoustic coupling constants and attenuation of ultrasonic waves due to thermo-elastic relaxation and phonon–phonon interaction mechanisms have been calculated in the temperature range 100 K–500 K. The obtained results of present investigation have been compared with available other similar type of materials.

The structural and dynamical properties of aluminosilicate melts: Insight via molecular dynamic simulation

We have studied the structural and dynamical characteristics of xAl2O3(1-x)SiO2 system by means of molecular dynamics simulation at 3000 K using the Born-Mayer potentials. The structural properties have been analysed through the radial distribution function and structural factor. The simulation shows that our results are in good agreement with previous experimental and simulated data. The dynamical heterogeneity (DH) is investigated via the analysis of mobile, immobile, and random atoms. Our simulation indicates that the liquids exists dynamical heterogeneity.

Hugoniot States and Mie–Grüneisen Equation of State of Iron Estimated Using Molecular Dynamics

The objective of this study was to develop a micromechanical approach for determining the Mie–Grüneisen EOS parameters of iron under the Hugoniot states. The multiscale shock technique (MSST) coupled with molecular dynamics (MD) simulations was employed to describe the shocked Hugoniot relation of single-crystal (SC) and nanocrystalline (NC) iron under high pressures. The Mie–Grüneisen equation of state (EOS) parameters, the cold pressure (Pc), the cold energy (Ec), the Grüneisen coefficient (γ), and the melting temperature (Tm) are discussed. The error between SC and NC iron results was found to be less than 1.5%. Interestingly, the differences in Hugoniot state (PH) and the internal energy between SC and NC iron were insignificant, which shows that the effect of grain size (GS) under high pressures was not significant. The Pc and Ec of SC and NC iron calculated based on the Morse potential were almost the same with those calculated based on the Born–Mayer potential; however, those calculated based on the Born–Mayer potential were a little larger at high pressures. In addition, several empirical and theoretical models were compared for the calculation of γ and Tm. The Mie–Grüneisen EOSs were shown on the 3D contour space; the pressure obtained with the Hugoniot curves as the reference was larger than that obtained with the cold curves as the reference.

Pressure and size dependent investigation of ultrasonic and thermal properties of ScRu intermetallic

Abstract The present work is focused on the determination of elastic, mechanical, ultrasonic and thermal properties of ScRu intermetallic under the variation of pressure 0–60 GPa and particle size 5–40 nm. Initially, the second order elastic constants (SOECs) have been computed under a potential model approach, in which interaction potential is defined by Coulomb and Born–Mayer potentials. Later on, the estimation of mechanical, ultrasonic and thermo-physical parameters has been performed using SOECs. The ultrasonic velocities are estimated in the same pressure/particle size range for wave propagation along 〈100〉 crystallographic direction. It is found that elastic constants, ultrasonic velocities, Debye average velocity, specific heat at constant volume, thermal energy density, thermal conductivity and melting point enhance with increase in pressure and decay in particle size in chosen intermetallic. The analysis of the obtained results reveals that the elastic, mechanical and thermal properties of ScRu intermetallic shall enhance effectively under pressure in comparison to decay in particle size.

Structural and dynamic properties of lithium silicate liquid: A view from molecular dynamics simulation

In this work, we have investigated the liquid lithium silicate by the method of molecular dynamics simulation (MD) using the Born-Mayer pairwise potentials under compression. The simulations have been carried out by systems including various pressure values from 5 to 30 GPa. The microstructure of lithium silicate was clarified through the thorough analysis of short-range order (SRO) and intermediate range order (IRO). The short-range order was investigated through factors such as pair radial distribution functions (PRDFs), coordination distributions, angular distributions. The results show that the structure of the system has a transformation from low-coordination to high-coordination under the influence of compression. Besides, the analysis of intermediate range order shows that the structure network in model consists of SiOx and LiOx units connected to others via an Oxygen atom. In the case for the intermediate range order, the fraction of OTy bond calculated under compression shows that their bonding angle and bond length are very little dependent on the pressure changes. Furthermore, the dynamics of liquid lithium silicates calculated through the diffusion coefficients of the atoms shows that there is a dependence of atomic mobility on pressure. The obtained results of simulations are in good agreement with previous experimental and simulated data.

The microstructure of liquid Lead Silicate under PbO content

The structural characteristics of liquid lead silicate xPbO(1-x)SiO2 are performed by means of molecular dynamics simulation at ambient pressure using the Born-Mayer pairwise potentials. The simulations have been performed on the systems which include different samples with a large range of PbO content ( 0.05 ⩽ x ⩽0.75). The short and intermediate range order in liquid xPbO(1-x)SiO2 have been analysed via pair radial distribution function (PRDFs), coordination distribution, angular distribution and bond length distribution. Calculations show that most of the basic structural units in liquid lead silicate network are SiO4, PbO2 and PbO3 at low ratio of PbO and SiO4, PbO3 and PbO4 at high ratio of PbO. The distribution of O-T-O bond angle and T-O bond length (T is Si or Pb) in SiO4, PbO4 and PbO5 basic structural units are slightly changed when PbO content increase. In intermediate range order, the topology structure of OTy linkages (y=2,3,4) is also investigated in detail.

Anharmonic Properties of Oxides Having Face Centered Cubic Crystal Structure of Fourth Order

A theory has been evolved for obtaining anharmonic properties of oxides having face centered cubic crystal symmetry using long-range Coulomb and short-range Born-Mayer potentials starting from the nearest-neighbour distance and hardness parameter. The fourth order elastic constants are obtained for oxides of Cd, Co, Fe, Nb, Ni, Te, Ti and Zr at elevated temperature. The room temperature data are utilized for obtaining the first order pressure derivatives of second and third order elastic constants, the second order pressure derivatives of second order elastic constants and partial contractions of these oxides. The results are presented and discussed.

Differentiative Study of Anharmonic Properties of Oxides Having Face Centered Cubic Crystal Structure of Third and Fourth Order

A theory has been evolved for obtaining anharmonic properties of oxides having face centered cubic crystal symmetry using long-range Coulomb and short-range Born-Mayer potentials starting from the nearest-neighbour distance and hardness parameter. The second order elastic constants are obtained for oxides of Cd, Co, Fe, Nb, Ni, Te, Ti and Zr at elevated temperature. The room temperature data are utilized for obtaining the first order pressure derivatives of second order elastic constants, the second order pressure derivatives of second order elastic constants and partial contractions of these oxides. The results are presented and discussed.

Calculation of liquidus curve in phase diagram LiCl-KCl by molecular dynamics simulation

ABSTRACTThe paper is devoted to the molecular dynamics calculations of the liquidus curve for the LiCl-KCl binary mixture. The two-phase simulations of the initial cell in an NPT ensemble were performed. Pairwise interactions are derived from the second-order Møller-Plesset perturbation theory and are well described by the Born–Mayer potential. The liquid–solid equilibria were observed upon heating of two crystals of pure components with runs duration of 10 ns. The eutectic point was found to be close to the experimental value.

Mechanical and Thermophysical Properties of ScM (M: Ru, Rh, Pd, Ag) Intermetallics

In this paper, we have investigated the elastic, mechanical, ultrasonic, and thermophysical properties of B2 structured scandium based intermetallic compounds ScM (M = Ru, Rh, Pd, Ag) at 300 K. Initially, the elastic constants were determined under potential model approach considering the interaction up to second nearest neighbors defined by Coulomb and Born–Mayer potential. The second order elastic constants (SOECs) were used to find the mechanical parameters such as shear modulus, bulk modulus, Poisson’s ratio, Young’s modulus, Pugh’s indicator, Zener ratio, Vicker’s hardness, Cauchy’s pressure, and Lame modulus in ScM intermetallic compounds. Further, SOECs were applied to compute the ultrasonic velocities and Debye velocity for wave transmission through ScM along ⟨100⟩ orientation. We have also evaluated thermal conductivity, thermal expansion coefficient, melting point, and thermal relaxation time of the chosen compounds. Finally, the ultrasonic attenuation was estimated using thermo-elastic relaxation and phonon–phonon interaction mechanisms at room temperature. The mechanical properties of ScM were discussed and analyzed on the basis of obtained elastic constants while their ultrasonic properties were discussed in connection with elastic and thermal properties.

Shock Hugoniot and Mie-Grüneisen EOS of TiAl alloy: A molecular dynamics approach

Molecular dynamics (MD) simulations coupling multi-scale shock technique (MSST) are performed to study the shock Hugoniot and Mie-Grüneisen equation of state (EOS) for TiAl alloy. The accuracy of the EAM potential for TiAl is examined by both melting temperature at a free pressure and Hugoniot curve. The material composition seriously affects the linear relation of shock wave velocity and particle velocity, Hugoniot curve, and internal energy. The Born-Mayer potential and Morse potential both can describe the cold curve at lower compressions, while the cold curve described via the Born-Mayer potential is larger than that of Morse potential at higher compressions. The shock melting temperature (Tm) is totally determined by Grüneisen coefficient γ, which shows an opposite trend as compared with the increasing Tm at the whole compressions. Mie-Grüneisen EOS presents a concave surface in pressure – specific volume – internal energy (P-V-E) space, which is independent of the reference curves utilized the cold curve and Hugoniot curve.

Thermal Conductivity of Alkali Metal Chlorides: Calculation with Molecular Dynamics Method

The classical molecular dynamics method was used to calculate the thermal conductivity of molten salts MCl (M = Li, Na, K, Rb, Cs) in the temperature range of two hundred degrees above the melting temperatures. The simulated system had 4000 nonequivalent ions (2000 metal and chlorine ions each) with periodic boundary conditions. The Born–Mayer potential with the Coulomb term was used in the simulation. It is shown that the thermal conductivity of alkali metal chlorides decreases with an increase in the cation number in line Li+ → Na+ → K+ → Rb+ → Cs+. Moreover, the thermal conductivity for all melts weakly depends on temperature.

Structure elucidation and construction of isomerisation pathways in small to moderate-sized (6-27) MgO nanoclusters: an adaptive mutation simulated annealing based analysis with quantum chemical calculations.

Determination of global minimum structures and elucidation of reaction paths or minimum energy paths between low-lying minima are of great chemical importance. To that end, we have used our own Adaptive Mutation Simulated Annealing method to determine the global minimum and the minimum energy paths for various isomerisation reactions for small to moderate-sized (MgO)n (n = 6-27) clusters, using the Born-Mayer potential with suitable parameter values. The minimum energy structures obtained by us match well with previously reported data and are used as guess structures for further optimisation at the DFT level (using the B3LYP functional and DGDZVP basis set). Our optimised structures are found to match very well with the further DFT optimised structures, where the comparison is done by determining the root mean square deviation values as well as the radial distribution function profiles. A scheme is proposed to determine the minimum energy paths for isomerisation reactions for some cluster sizes where the transition state/s obtained by us, at very low computational cost, match well with those obtained from further optimisation using DFT calculations. We have shown the efficacy of our method in determining the reaction pathways, even for cases that involve multi-step reactions.

Comparative Study of Anharmonic Properties of Oxides Having Face Centered Cubic Crystal Structure of Second and Third Order

A theory has been evolved for obtaining anharmonic properties of oxides having face centered cubic crystal symmetry using long-range Coulomb and short-range Born-Mayer potentials starting from the nearest-neighbour distance and hardness parameter. The second order elastic constants are obtained for oxides of Cd, Co, Fe, Nb, Ni, Te, Ti and Zr at elevated temperature. The room temperature data are utilized for obtaining the first order pressure derivatives of second order elastic constants, the second order pressure derivatives of second order elastic constants and partial contractions of these oxides. The results are presented and discussed.

Anharmonic Properties of Oxides Having Face Centered Cubic Crystal Structure

A theory has been evolved for obtaining anharmonic properties of oxides having face centered cubic crystal symmetry using long-range Coulomb and short-range Born-Mayer potentials starting from the nearest-neighbour distance and hardness parameter. The second ,third and fourth order elastic constants are obtained for oxides of Cd, Co, Fe, Nb, Ni, Te, Ti and Zr at elevated temperature. The room temperature data are utilized for obtaining the first order pressure derivatives of second and third order elastic constants, the second order pressure derivatives of second order elastic constants and partial contractions of these oxides. The results are presented and discussed.

Elastic and thermal properties of carbides of U, Pu, and Am

In this study, we investigated the behaviors of three representative actinide monocarbides (AnCs, where An = U, Pu, and Am) in terms of their superior mechanical and thermo-elastic properties. Coulomb and Born–Mayer potentials were used to calculate the temperature-dependent second order and third order elastic constants up to the second nearest neighbor. The Voigt–Reuss–Hill approximation was employed to compute the values of Young's modulus (Y), Zener anisotropy ratio (A), shear modulus (G), bulk modulus (B), Poisson's ratio (σ), and Pugh's indicator (B/G) using second order elastic constants. The Born stability criteria and Vicker's hardness parameter (Hν) were analyzed to determine the strength and nature of the materials. The Debye average velocities and Breazeale's nonlinearity parameters were calculated in the temperature range from 100 to 500 K. Thermal properties such as the lattice thermal conductivity, thermal relaxation time, crystal energy density, and acoustic coupling constant were computed at different temperatures and along various directions. The longitudinal and shear components of ultrasonic attenuation were evaluated along the three crystallographic directions comprising <100>, <110>, and <111>. The temperature- and direction-dependent ultrasonic properties were correlated with other thermo-physical properties to extract important information such as the material strength and thermal conductivity in order to assess the microstructural quality and nature of the materials, which are useful for industrial applications.