First-principles calculation of second-order elastic constants and equations of state for lithium azide, LiN3 , and lead azide, Pb(N3 )2

2009 ◽  
Vol 110 (10) ◽  
pp. 1916-1922 ◽  
Author(s):  
W. F. Perger
Keyword(s):  
Elastic Constants ◽  
First Principles ◽  
Equations Of State ◽  
Second Order ◽  
First Principles Calculation ◽  
Lead Azide

scholarly journals First Principles Computations of Second-Order Elastic Constants (SOEC) and Equations of State of Rutile TiO2

2011 ◽  
Vol 2011 ◽  
pp. 1-7 ◽  
Author(s):  
Ghous Narejo ◽  
Warren F. Perger
Keyword(s):  
Equation Of State ◽  
Elastic Constants ◽  
First Principles ◽  
Equations Of State ◽  
Second Order ◽  
Lattice Parameters ◽  
Experimental Results ◽  
Basis Sets ◽  
Computational Results ◽  
Rutile Tio2

First principles computations of second-order elastic constants (SOECs) and bulk moduli (B) are carried out by ELASTCON and equation of state (EOS) programs. Computational results of lattice parameters, elastic constants, and bulk moduli are obtained with a wide variety of potentials and a limited combination of basis sets and are compared with computational and experimental results by other researchers in the field. DFT hybrid potentials provided the best comparison with the experiment.

FIRST-PRINCIPLES HIGH-PRESSURE ELASTIC AND THERMODYNAMIC PROPERTIES OF TANTALUM

2011 ◽  
Vol 25 (10) ◽  
pp. 1393-1407 ◽  
Author(s):  
JING-HE WU ◽  
XIAN-LIN ZHAO ◽  
YOU-LIN SONG ◽  
GUO-DONG WU
Keyword(s):  
Thermodynamic Properties ◽  
Elastic Constants ◽  
First Principles ◽  
Equations Of State ◽  
Debye Model ◽  
Thermal Expansivity ◽  
Orbital Method ◽  
Full Potential ◽  
Body Centered Cubic ◽  
Theoretical Results

The all-electron full-potential linearized muffin-tin orbital method, by means of quasi-harmonic Debye model, is applied to investigate the elastic constant and thermodynamic properties of body-centered-cubic tantalum (bcc Ta). The calculated elastic constants of bcc Ta at 0 K is consistent with the previous experimental and theoretical results. Our calculations give the correct trends for the pressure dependence of elastic constants. By using the convenient quasi-harmonic Debye model, we refined the thermal equations of state. The thermal expansivity and some other thermal properties agree well with the previous experimental and theoretical results.

Effect of Alloying Elements V, Cr and Ni on the Electronic Structure and Mechanical Properties of FeAl from First-Principles Calculation

2014 ◽  
Vol 887-888 ◽  
pp. 378-383 ◽  
Author(s):  
Yu Chen ◽  
Zheng Jun Yao ◽  
Ping Ze Zhang ◽  
Dong Bo Wei ◽  
Xi Xi Luo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electronic Structure ◽  
Elastic Constants ◽  
First Principles ◽  
Density Functional ◽  
Valence Bond ◽  
Ternary Alloys ◽  
First Principles Calculation ◽  
Structure Stability ◽  
Alloying Element

The structure stability, mechanical properties and electronic structures of B2 phase FeAl intermetallic compounds and FeAl ternary alloys containing V, Cr or Ni were investigated using first-principles density functional theory calculations. Several models are established. The total energies, cohesive energies, lattice constants, elastic constants, density of states, and the charge densities of Fe8Al8 and Fe8XAl7 ( X=V, Cr, Ni ) are calculated. The stable crystal structures of alloy systems are determined due to the cohesive energy results. The calculated lattice contants of Fe-Al-X ( X= V, Cr, Ni) were found to be related to the atomic radii of the alloy elements. The calculation and analysis of the elastic constants showed that ductility of FeAl alloys was improved by the addition of V, Cr or Ni, the improvement was the highest when Cr was used. The order of the ductility was as follows: Fe8CrAl7 > Fe8NiAl7 > Fe8VAl7 > Fe8Al8. The results of electronic structure analysis showed that FeAl were brittle, mainly due to the orbital hybridization of the s, p and d state electron of Fe and the s and p state electrons of Al, showing typical characteristics of a valence bond. Micro-mechanism for improving ductility of FeAl is that d orbital electron of alloying element is maily involved in hybridization of FeAl, alloying element V, Cr and Ni decrease the directional property in bonding of FeAl.

First Principles Calculation of Elastic Constants of Monoclinic HfO2Thin Film

2013 ◽  
Vol 33 (1) ◽  
pp. 0131001
Author(s):  
蔺玲 Lin Ling ◽  
邵淑英 Shao Shuying ◽  
李静平 Li Jingping
Keyword(s):  
Elastic Constants ◽  
First Principles ◽  
First Principles Calculation

Novel elastic evolution of carbide Mo2Ga2C under pressure: Ab initio theoretical investigation

2019 ◽  
Vol 33 (30) ◽  
pp. 1950358
Author(s):  
Rui Wu ◽  
Hai-Chen Wang ◽  
Yan Yang ◽  
Li Ma ◽  
Shan Jiang ◽  
...  
Keyword(s):  
Phase Transition ◽  
High Pressure ◽  
Elastic Constants ◽  
Pressure Dependence ◽  
First Principles ◽  
Phonon Mode ◽  
First Principles Calculation ◽  
Max Phases ◽  
Transverse Acoustic ◽  
Phonon Structure

The pressure dependence of elastic properties of Mo2Ga2C is studied via first-principles calculation. The present investigation shows that differing from other MAX phases, in Mo2Ga2C the [Formula: see text] is larger than [Formula: see text], because of the strong Ga–Ga interlayer bonds along [Formula: see text]-axis. Moreover, under pressure, the [Formula: see text] increases more rapidly, originating from the faster strengthening of Ga–Ga bonds. Interestingly, elastic constants [Formula: see text] soften under high pressure (more than 20 GPa). Especially, the calculated phonon structure demonstrates that transverse acoustic (TA) phonon mode also softens under pressure, implying possible phase transition. The reduction of [Formula: see text] and softening of phonon mode are attributed to significantly weakened Mo–Mo interaction in contrast to the strengthening of Ga–Ga bonds under high pressure. Our present results further indicate that Mo2Ga2C is more ductile under pressure.

ElaStic: A tool for calculating second-order elastic constants from first principles

2013 ◽  
Vol 184 (8) ◽  
pp. 1861-1873 ◽  
Author(s):  
Rostam Golesorkhtabar ◽  
Pasquale Pavone ◽  
Jürgen Spitaler ◽  
Peter Puschnig ◽  
Claudia Draxl
Keyword(s):  
Elastic Constants ◽  
First Principles ◽  
Second Order
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