First-principles calculation of mechanical properties of simulated debris ZrxU1−xO2

2019 ◽  
Vol 56 (9-10) ◽  
pp. 915-921 ◽  
Author(s):  
Mitsuhiro Itakura ◽  
Hiroki Nakamura ◽  
Toru Kitagaki ◽  
Takanori Hoshino ◽  
Masahiko Machida
Keyword(s):  
Mechanical Properties ◽  
First Principles ◽  
First Principles Calculation

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.

Mechanical Properties and Size Effects of ZnO Nanowires Studied by First-Principles Calculation

2010 ◽  
Vol 654-656 ◽  
pp. 1670-1673
Author(s):  
Zhan Jun Gao ◽  
You Song Gu ◽  
Yue Zhang
Keyword(s):  
Mechanical Properties ◽  
First Principles ◽  
Size Effects ◽  
Density Functional ◽  
Elastic Moduli ◽  
Axial Direction ◽  
Zno Nanowires ◽  
First Principles Calculation ◽  
Different Diameters ◽  
Ground State Energies

First-principles density functional calculations were performed to investigate mechanical properties of ZnO nanowires and the size effects. Structural optimizations were performed first, and a series of strains were applied to the nanowires in the axial direction. The ground state energies were calculated and the elastic moduli of ZnO nanowires were obtained from the energy versus strain curves. It is found that the elastic moduli of the ZnO nanowires with three different diameters (1.2, 1.5 and 1.8nm) are 136.3, 138.7 and 138.0 GPa, respectively, and that of bulk ZnO along [0001] direction is 140.1 GPa. The elastic modulus of ZnO nanowire is slightly lower than that of the bulk and it decreases as the diameter decreases. Comparisons to experimental results and theoretical predications are made.

scholarly journals First-principles calculation for mechanical properties of metal dihydrides

2012 ◽  
Vol 61 (10) ◽  
pp. 108801
Author(s):  
Dai Yun-Ya ◽  
Yang Li ◽  
Peng Shu-Ming ◽  
Long Xing-Gui ◽  
Zhou Xiao-Song ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
First Principles ◽  
First Principles Calculation

scholarly journals Effects of Doped Elements (Si, Cr, W and Nb) on the Stability, Mechanical Properties and Electronic Structures of MoAlB Phase by the First-Principles Calculation

Materials ◽  
2020 ◽  
Vol 13 (19) ◽  
pp. 4221
Author(s):  
Yongxin Jian ◽  
Zhifu Huang ◽  
Yu Wang ◽  
Jiandong Xing
Keyword(s):  
Mechanical Properties ◽  
Chemical Bonding ◽  
First Principles ◽  
Electronic Structures ◽  
Density Functional ◽  
Formation Enthalpy ◽  
First Principles Calculation ◽  
Elemental Doping ◽  
The Stability ◽  
W Doping

First-principles calculations based on density functional theory (DFT) have been performed to explore the effects of Si, Cr, W, and Nb elements on the stability, mechanical properties, and electronic structures of MoAlB ternary boride. The five crystals, with the formulas of Mo4Al4B4, Mo4Al3SiB4, Mo3CrAl4B4, Mo3WAl4B4, and Mo3NbAl4B4, have been respectively established. All the calculated crystals are thermodynamically stable, according to the negative cohesive energy and formation enthalpy. By the calculation of elastic constants, the mechanical moduli and ductility evolutions of MoAlB with elemental doping can be further estimated, with the aid of B/G and Poisson’s ratios. Si and W doping cannot only enhance the Young’s modulus of MoAlB, but also improve the ductility to some degree. Simultaneously, the elastic moduli of MoAlB are supposed to become more isotropic after Si and W addition. However, Cr and Nb doping plays a negative role in ameliorating the mechanical properties. Through the analysis of electronic structures and chemical bonding, the evolutions of chemical bondings can be disclosed with the addition of dopant. The enhancement of B-B, Al/Si-B, and Al/Si-Mo bondings takes place after Si substitution, and W addition apparently intensifies the bonding with B and Al. In this case, the strengthening of chemical bonding after Si and W doping exactly accounts for the improvement of mechanical properties of MoAlB. Additionally, Si doping can also improve the Debye temperature and melting point of the MoAlB crystal. Overall, Si element is predicted to be the optimized dopant to ameliorate the mechanical properties of MoAlB.

STRUCTURAL, ELASTIC AND MECHANICAL PROPERTIES OF TMN (TM = Ti, V, Cr): A DFT STUDY

2013 ◽  
Vol 27 (22) ◽  
pp. 1350158 ◽  
Author(s):  
ZHAO-YONG JIAO ◽  
YI-JUN NIU ◽  
SHU-HONG MA ◽  
XIAO-FEN HUANG
Keyword(s):  
Mechanical Properties ◽  
Transition Metal ◽  
First Principles ◽  
High Hardness ◽  
First Principles Calculation ◽  
Dft Study ◽  
Metal Nitrides ◽  
Transition Metal Nitrides ◽  
Metallic Bonding

Mechanical properties and the effect of metallic bonding on the hardness of transition-metal nitrides ( TiN , VN and CrN ) compounds are studied using the first-principles calculation. Present results show that these transition-metal nitrides are mechanically stable and the VN and CrN are ductile, whereas TiN is predicted to be brittle. Moreover, it is found that the high hardness of TiN , VN and CrN exhibits a remarkable decrease with transition-metal changed from Ti to Cr , and the metallic d–d interactions play important roles on determining the hardness of transition-metal nitrides.

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