The structural, elastic and thermodynamic properties of intermetallic phases in Mg–Sn–Si–Ca(Sr) alloys: A first-principles study

2018 ◽  
Vol 32 (22) ◽  
pp. 1850246
Author(s):  
Yan Li ◽  
Yuhong Zhao ◽  
Hua Hou ◽  
Xiaomin Yang
Keyword(s):  
Mechanical Properties ◽  
Thermodynamic Properties ◽  
First Principles ◽  
Poisson Ratio ◽  
Debye Model ◽  
Intermetallic Phases ◽  
First Principles Calculations ◽  
Formation Enthalpies ◽  
Anisotropy Index ◽  
Cohesive Energies

The structural, elastic and thermodynamic properties of Mg2Si, Mg2Sn, CaMgSi and MgSnSr phases in Mg–Sn–Si–Ca(Sr) alloys have been investigated by implementing first-principles calculations. Formation enthalpies and cohesive energies show that MgSnSr has the strongest alloying ability and CaMgSi has the highest structural stability. The bulk modulus B, shear modulus G, Young’s modulus E, G/B, Poisson ratio [Formula: see text], anisotropy index A[Formula: see text] are estimated after evaluating the elastic constants. The mechanical properties are further analyzed and discussed. Finally, the Gibbs free energy and Debye temperature of these phases are calculated by means of the quasi-harmonic Debye model in temperature ranging from 0 K to 1000 K.

Structural, elastic and thermodynamic properties of A15-type compounds V3X (X = Ir, Pt and Au) from first-principles calculations

2016 ◽  
Vol 30 (35) ◽  
pp. 1650414 ◽  
Author(s):  
Mingliang Wang ◽  
Zhe Chen ◽  
Dong Chen ◽  
Cunjuan Xia ◽  
Yi Wu
Keyword(s):  
Thermodynamic Properties ◽  
Debye Temperature ◽  
First Principles ◽  
Density Functional ◽  
Coefficient Of Thermal Expansion ◽  
Local Density ◽  
Debye Model ◽  
First Principles Calculations ◽  
Generalized Gradient ◽  
Experimental Values

The structural, elastic and thermodynamic properties of the A15 structure V3Ir, V3Pt and V3Au were studied using first-principles calculations based on the density functional theory (DFT) within generalized gradient approximation (GGA) and local density approximation (LDA) methods. The results have shown that both GGA and LDA methods can process the structural optimization in good agreement with the available experimental parameters in the compounds. Furthermore, the elastic properties and Debye temperatures estimated by LDA method are typically larger than the GGA methods. However, the GGA methods can make better prediction with the experimental values of Debye temperature in V3Ir, V3Pt and V3Au, signifying the precision of the calculating work. Based on the E–V data derived from the GGA method, the variations of the Debye temperature, coefficient of thermal expansion and heat capacity under pressure ranging from 0 GPa to 50 GPa and at temperature ranging from 0 K to 1500 K were obtained and analyzed for all compounds using the quasi-harmonic Debye model.

First-Principles Calculations of Elastic and Thermodynamic Properties of Cubic CdTe

2011 ◽  
Vol 268-270 ◽  
pp. 886-891
Author(s):  
Ben Hai Yu ◽  
Dong Chen
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Bulk Modulus ◽  
First Principles ◽  
Debye Model ◽  
First Principles Calculations ◽  
Lattice Constants ◽  
Temperature And Pressure ◽  
The Relationship

the equilibrium lattice constants, elastic and thermodynamic properties of cubic CdTe are systemically investigated at high temperature using the plane-wave pseudopotential method as well as the quasi-harmonic Debye model. The bulk modulus of CdTe are calculated as a function of temperature up to 1000K, the relationship between bulk modulusBand pressure is also obtained. The results gained from this model will provide overall predictions accurately for the temperature and pressure dependence of various quantities such as the bulk modulus, the heat capacity and the thermal expansion coefficient. More over, the dependences between Debye temperature and temperature are also successfully obtained. Our results are compared with the experimental data and discussed in light of previous works.

scholarly journals First-principles and CALPHAD-type study of the Ir-Mo and Ir-W systems

2020 ◽  
Vol 56 (1) ◽  
pp. 109-118 ◽  
Author(s):  
Y.-Y. Huang ◽  
B. Wu ◽  
F. Li ◽  
L.-L. Chen ◽  
Z.-X. Deng ◽  
...  
Keyword(s):  
Experimental Data ◽  
Thermodynamic Properties ◽  
Thermodynamic Property ◽  
Phase Equilibria ◽  
First Principles ◽  
Critical Evaluation ◽  
Intermetallic Phases ◽  
First Principles Calculations ◽  
Property Data ◽  
Self Consistent

This study presents the thermodynamic modeling of the Ir-Mo and Ir-W systems by means of the CALPHAD (CALculation of PHAse Diagrams) approach supported with the first-principles calculations. A critical evaluation of the phase equilibria and the thermodynamic property data in literature was conducted for both systems. Due to the lack of experimental data, the first-principles calculations were applied to obtain the enthalpies of the solid and intermetallic phases. The thermodynamic parameters were assessed using the PARROT module of Thermo-Calc. A set of self-consistent parameters for the Ir-Mo and Ir-W systems was obtained after the optimization. Satisfactory agreement between the calculated results and the experimental data, including phase equilibria and thermodynamic properties was achieved.

THERMODYNAMIC PROPERTIES OF MC (M = V, Nb, Ta): FIRST-PRINCIPLES CALCULATIONS

2013 ◽  
Vol 27 (19) ◽  
pp. 1341035 ◽  
Author(s):  
YONG CAO ◽  
JINGCHUAN ZHU ◽  
YONG LIU ◽  
ZHISHEN LONG
Keyword(s):  
Experimental Data ◽  
Heat Capacity ◽  
Thermodynamic Properties ◽  
Bulk Modulus ◽  
First Principles ◽  
Linear Expansion ◽  
Debye Model ◽  
Linear Expansion Coefficient ◽  
First Principles Calculations ◽  
Temperature Dependences

Through the quasi-harmonic Debye model, the pressure and temperature dependences of linear expansion coefficient, bulk modulus, Debye temperature and heat capacity have been investigated. The calculated thermodynamic properties were compared with experimental data and satisfactory agreement is reached.

scholarly journals First-principles calculations of structural, electronic, magnetic and elastic properties of Mo 2 FeB 2 under high pressure

2018 ◽  
Vol 5 (7) ◽  
pp. 172247
Author(s):  
Bin Wang ◽  
Benyuan Ma ◽  
Wei Song ◽  
Zhe Fu ◽  
Zhansheng Lu
Keyword(s):  
Heat Capacity ◽  
High Pressure ◽  
Elastic Properties ◽  
First Principles ◽  
Dynamic Properties ◽  
Magnetic Moments ◽  
Debye Model ◽  
Ferromagnetic Phase ◽  
First Principles Calculations ◽  
Anisotropy Index

The structural, electronic, magnetic and elastic properties of Mo 2 FeB 2 under high pressure have been investigated with first-principles calculations. Furthermore, the thermal dynamic properties of Mo 2 FeB 2 were also studied with the quasi-harmonic Debye model. The volume of Mo 2 FeB 2 decreases with the increase in pressure. Using the analysis of the density of the states, atom population and Mulliken overlap population, it is observed that as the pressure increases, the B–B bonds are strengthened and the B–Mo covalency decreases. Moreover, for all pressures, Mo 2 FeB 2 is detected in the anti-ferromagnetic phase and the magnetic moments decrease with the increase in pressure. The calculated bulk modulus, shear modulus, Young's modulus, Poisson's ratio and universal anisotropy index all increase with the increase in pressure. From thermal expansion coefficient analysis, it is found that Mo 2 FeB 2 shows good volume invariance under high pressure and temperature. The examination of the dependence of heat capacity on the temperature and pressure shows that heat capacity is more sensitive to temperature than to pressure.

First-Principles Investigations on Structural, Elastic, and Thermodynamic Properties of Ce-La Alloys Under High Pressure

2014 ◽  
Vol 69 (1-2) ◽  
pp. 52-60
Author(s):  
Li-Qin Zhang ◽  
Yan Cheng ◽  
Zhen-Wei Niu ◽  
Guang-Fu Ji
Keyword(s):  
Heat Capacity ◽  
High Pressure ◽  
Thermal Expansion ◽  
Thermodynamic Properties ◽  
Electronic Properties ◽  
Ground State ◽  
First Principles ◽  
Debye Model ◽  
First Principles Calculations ◽  
Charge Densities

The structural stability, thermodynamic, elastic, and electronic properties of cerium (Ce)- lanthanum (La) alloys were investigated for different Ce/La ratios under pressure by first-principles calculations using on-the-fly (OTF) pseudopotential and general gradient approximation (GGA). The ground-state properties of lanthanum and cerium obtained by minimizing the total energy agree favourably with other work.We derived the elastic constants, bulk modulus, and shear modulus of the La-Ce alloys for different Ce/La ratios. Using the quasi-harmonic Debye model, the thermodynamic properties of the La-Ce alloys including the thermal expansion coefficient α and heat capacity Cv are successfully obtained in the temperature range from 0 K to 1000 K. Furthermore, the electronic properties such as density of states and charge densities were also studied.

Structural and Mechanical Properties of Boron Nanotubes

2003 ◽  
Vol 791 ◽  
Author(s):  
Matthew H. Evans ◽  
John D. Joannopoulos ◽  
Sokrates T. Pantelides
Keyword(s):  
Mechanical Properties ◽  
Carbon Nanotubes ◽  
Ground State ◽  
First Principles ◽  
Elastic Response ◽  
Unusual Property ◽  
First Principles Calculations ◽  
Ground State Degeneracy ◽  
Cohesive Energies ◽  
Novel Structures

ABSTRACTWe report the results of first-principles calculations showing that boron can form a wide variety of metastable planar and tubular forms with unusual electronic and mechanical properties. The preferred planar structure is a buckled triangular lattice that breaks the threefold ground state degeneracy of the flat triangular plane. When the plane is rolled into a tube, the ground state degeneracy leads to a strong chirality dependence of the binding energy and elastic response, an unusual property that is not found in carbon nanotubes. The achiral (n, 0) tubes derive their structure from the flat triangular plane. The achiral (n, n) boron nanotubes arise from the buckled plane, and have large cohesive energies and novel structures as a result.

scholarly journals First-principles Study of Vickers Hardness and Thermodynamic Properties of Ti3SnC2 Polymorphs

2015 ◽  
Vol 7 (3) ◽  
pp. 53-64 ◽  
Author(s):  
M. A. Rayhan ◽  
M. A. Ali ◽  
S. H. Naqib ◽  
A. K. M. A. Islam
Keyword(s):  
Thermodynamic Properties ◽  
Vickers Hardness ◽  
First Principles ◽  
Applied Pressure ◽  
Theoretical Data ◽  
Debye Model ◽  
Covalent Bonding ◽  
First Principles Calculations ◽  
Specific Heats ◽  
Strong Covalent Bonding

We have investigated Vickers hardness and the thermodynamic properties of the recently discovered nanolaminate carbide Ti3SnC2 polymorphs using the first-principles calculations. The chemical bonding shows a combination of covalent, ionic and metallic types. The strong covalent bonding is mainly responsible for high Vickers hardness of Ti3SnC2 polymorphs. Thermodynamic properties are studied using the quasi-harmonic Debye model. The variation of bulk modulus, thermal expansion coefficient, specific heats, and Debye temperature with applied pressure (P) and temperature (T) are investigated systematically within the ranges of 0 - 50 GPa and 0 - 1000 K. The calculated results have been compared with available experimental and theoretical data.

Sign in / Sign up

Export Citation Format

Share Document