Comparative study of 9R and 12R hexagonal diamond by first-principles calculations

2018 ◽  
Vol 32 (20) ◽  
pp. 1850211
Author(s):  
Qian Wang ◽  
Quan Zhang
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Comparative Study ◽  
Bulk Modulus ◽  
Elastic Constants ◽  
First Principles ◽  
Elastic Anisotropy ◽  
First Principles Calculations ◽  
Ideal Strength ◽  
Superhard Materials

The structural and mechanical properties of 9R diamond and 12R diamond have been investigated by using the first-principles calculations. The elastic constants, bulk modulus and Young’s modulus at various pressures have been investigated. The elastic anisotropy under pressure from 0 to 100 GPa has been studied. From our calculations, we found that 9R diamond and 12R diamond have similar high elastic constants and elastic modulus as lonsdaleite and diamond. The detailed ideal strength calculations show that 9R diamond and 12R diamond are intrinsic superhard materials.

First-Principles Study of the Mechanical Properties of ScAl Microalloyed by 4d-Transition Metals

2014 ◽  
Vol 852 ◽  
pp. 198-202
Author(s):  
Shuo Huang ◽  
Chuan Hui Zhang ◽  
Rui Zi Li ◽  
Jing Sun ◽  
Jiang Shen
Keyword(s):  
Mechanical Properties ◽  
Transition Metals ◽  
Shear Modulus ◽  
Bulk Modulus ◽  
Elastic Constants ◽  
First Principles ◽  
First Principles Calculations ◽  
Cauchy Pressure ◽  
Theoretical Results ◽  
Elastic Coefficients

The structural and elastic properties of B2 ScAl doped with Y, Zr, Nb, Mo, Tc, Ru, Rh, Pd, Ag and Cd elements are studied by using first-principles calculations. The calculated elastic coefficients of pure ScAl are consistent with other theoretical results. The results of elastic constants indicate that all the ScAl-based alloys discussed are mechanically stable. The bulk modulusB, shear modulusG, Youngs modulusY, Pugh ratioB/Gand Cauchy pressure (C12-C44) are investigated. It is found that the addition of Ru that prefers Al site in ScAl can increase the stiffness of ScAl and improve its ductility.

scholarly journals Mechanical and Thermal Conductivity Properties of Enhanced Phases in Mg-Zn-Zr System from First Principles

Materials ◽  
2018 ◽  
Vol 11 (10) ◽  
pp. 2010
Author(s):  
Shuo Wang ◽  
Yuhong Zhao ◽  
Huijun Guo ◽  
Feifei Lan ◽  
Hua Hou
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Shear Modulus ◽  
Bulk Modulus ◽  
Intermetallic Compounds ◽  
Elastic Constants ◽  
First Principles ◽  
Strengthening Phases ◽  
Zr Alloy ◽  
Zr Alloys

In this paper, the mechanical properties and minimum thermal conductivity of ZnZr, Zn2Zr, Zn2Zr3, and MgZn2 are calculated from first principles. The results show that the considered Zn-Zr intermetallic compounds are effective strengthening phases compared to MgZn2 based on the calculated elastic constants and polycrystalline bulk modulus B, shear modulus G, and Young’s modulus E. Meanwhile, the strong Zn-Zr ionic bondings in ZnZr, Zn2Zr, and Zn2Zr3 alloys lead to the characteristics of a higher modulus but lower ductility than the MgZn2 alloy. The minimum thermal conductivity of ZnZr, Zn2Zr, Zn2Zr3, and MgZn2 is 0.48, 0.67, 0.68, and 0.49 W m−1 K−1, respectively, indicating that the thermal conductivity of the Mg-Zn-Zr alloy could be improved as the precipitation of Zn atoms from the α-Mg matrix to form the considered Zn-Zr binary alloys. Based on the analysis of the directional dependence of the minimum thermal conductivity, the minimum thermal conductivity in the direction of [110] can be identified as a crucial short limit for the considered Zn-Zr intermetallic compounds in Mg-Zn-Zr alloys.

First-Principles Calculations of Elastic Properties of HoBi and ErBi

2013 ◽  
Vol 664 ◽  
pp. 672-676
Author(s):  
De Ming Han ◽  
Gang Zhang ◽  
Li Hui Zhao
Keyword(s):  
Shear Modulus ◽  
Physical Properties ◽  
Bulk Modulus ◽  
Elastic Properties ◽  
Lattice Constant ◽  
Elastic Constants ◽  
First Principles ◽  
Energy Band ◽  
First Principles Calculations ◽  
Future Work

We present first-principles investigations on the elastic properties of XBi (X=Ho, Er) compounds. Basic physical properties, such as lattice constant, elastic constants (Cij), isotropic shear modulus (G), bulk modulus (B), Young’s modulus (Y), Poisson’s ratio (υ), and Anisotropy factor (A) are calculated. The calculated energy band structures show that the two compounds possess semi-metallic character. We hope that these results would be useful for future work on two compounds.

First-Principles Study of the Elastic Properties of Hexagonal Phase ScAx (A=H, He)

2013 ◽  
Vol 690-693 ◽  
pp. 1723-1727
Author(s):  
Kai Min Fan ◽  
Li Yang ◽  
Jing Tang ◽  
Qing Qiang Sun ◽  
Xiao Tao Zu
Keyword(s):  
Elastic Modulus ◽  
Shear Modulus ◽  
Bulk Modulus ◽  
First Principles ◽  
Poisson’S Ratio ◽  
Hexagonal Phase ◽  
Poisson's Ratio ◽  
First Principles Calculations ◽  
Charge Densities ◽  
Change Mechanism

First-principles calculations are performed to investigate the Young’s modulus, bulk modulus, shear modulus and Poisson’s ratio of hexagonal phase ScAx(A=H, He), where x=0, 0.0313, 0.125 and 0.25, represent the ratio of interstitial atoms A (A=H, He) to Sc atoms. The influences of hydrogen concentrations and helium concentrations on elastic modulus and Poisson’s ratio of ScAx(A=H, He) have been studied. The results indicate that hydrogen and helium have different effects on the elastic modulus of hexagonal phase scandium. The change mechanism of the Poisson’s ratio with the variation of the x ranging from 0 to 0.25 has also been studied in hexagonal phase ScAx(A=H, He). In addition, the changes in the charge densities of ScAxdue to the presence of hydrogen and helium have been calculated.

scholarly journals Elastic constants and mechanical properties of PEDOT from first principles calculations

2017 ◽  
Vol 139 ◽  
pp. 234-242 ◽  
Author(s):  
R.O. Agbaoye ◽  
P.O. Adebambo ◽  
J.O. Akinlami ◽  
T.A. Afolabi ◽  
Smagul Zh. Karazhanov ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Constants ◽  
First Principles ◽  
First Principles Calculations

Structural and elastic properties of Cu6Sn5 and Cu3Snfrom first-principles calculations

2009 ◽  
Vol 24 (7) ◽  
pp. 2361-2372 ◽  
Author(s):  
Jiunn Chen ◽  
Yi-Shao Lai ◽  
Ping-Feng Yang ◽  
Chung-Yuan Ren ◽  
Di-Jing Huang
Keyword(s):  
Electronic Structure ◽  
Elastic Modulus ◽  
Elastic Properties ◽  
First Principles ◽  
Elastic Anisotropy ◽  
Lattice Structure ◽  
Elastic Stiffness ◽  
First Principles Calculations ◽  
Atomic Lattice ◽  
Microstructure Effect

We investigated the elastic properties of two tin-copper crystalline phases, the η′-Cu6Sn5 and ε-Cu3Sn, which are often encountered in microelectronic packaging applications. The full elastic stiffness of both phases is determined based on strain-energy relations using first-principles calculations. The computed results show the elastic anisotropy of both phases that cannot be resolved from experiments. Our results, suggesting both phases have the greatest stiffness along the c direction, particularly showed the unique in-plane elastic anisotropy associated with the lattice modulation of the Cu3Sn superstructure. The polycrystalline moduli obtained using the Voigt-Reuss scheme are 125.98 GPa for Cu6Sn5 and 134.16 GPa for Cu3Sn. Our data analysis indicates that the smaller elastic moduli of Cu6Sn5 are attributed to the direct Sn–Sn bond in Cu6Sn5. We reassert the elastic modulus and hardness of both phases using the nanoindentation experiment for our calculation benchmark. Interestingly, the computed polycrystalline elastic modulus of Cu6Sn5 seems to be overestimated, whereas that of Cu3Sn falls nicely in the range of reported data. Based on the observations, the elastic modulus of Cu6Sn5 obtained from nanoindentation tests admit the microstructure effect that is absent for Cu3Sn is concluded. Our analysis of electronic structure shows that the intrinsic hardness and elastic modulus of both phases are dominated by electronic structure and atomic lattice structure, respectively.

Structural, Electronic, Elastic and Mechanical Properties of ScNi, ScPd and ScPt: A FP-LAPW Study

2014 ◽  
Vol 1047 ◽  
pp. 27-34 ◽  
Author(s):  
Bushra Fatima ◽  
Sunil Singh Chouhan ◽  
Nikita Acharya ◽  
S.P. Sanyal
Keyword(s):  
Mechanical Properties ◽  
Band Structure ◽  
Bulk Modulus ◽  
Ground State ◽  
First Principles ◽  
First Principles Calculations ◽  
Fermi Surfaces ◽  
First Order ◽  
Cauchy Pressure ◽  
Metallic Bonding

Systematic first principles calculations have been carried out to study the structural, electronic, elastic and mechanical properties of ScNi, ScPd and ScPt using FP-LAPW method within GGA. The ground state properties such as lattice constant, bulk modulus and first order pressure derivates of bulk modulus, were evaluated. The electronic and bonding patterns of these compounds have been analysed quantitatively from band structure and Fermi surfaces. It is clear from band structures that these compounds are metallic in nature. Ductility for these compounds is analysed by using Pugh’s criteria, Cauchy pressure (C12–C44) and Frantsevich rule. Amongst all these Sc compounds, ScNi is found to be most ductile due to the presence of strong metallic bonding.

First Principles Calculations of Phase Stabilities of YNi2 and YMgNi4

2010 ◽  
Vol 152-153 ◽  
pp. 1632-1635 ◽  
Author(s):  
Jian Gang Niu ◽  
Hai En Xiang ◽  
Xiao Ping Dong ◽  
Li Guan ◽  
Fei Xie
Keyword(s):  
Melting Point ◽  
Stress Relaxation ◽  
Bulk Modulus ◽  
Elastic Constants ◽  
First Principles ◽  
First Principles Calculations ◽  
Relative Stabilities ◽  
Ionic Contribution

First-principles calculations were performed to study the relative stabilities of YNi2 and YMgNi4.The calculated results show that YMgNi4 has the higher stability than YNi2, duing to stress relaxation and ionic contribution. The preferential stability of YMgNi4 has been confirmed by calculating elastic constants and melting points.The calculated results show that YMgNi4 has the larger bulk modulus and melting point than YNi2.

A comparative study on heterogeneous nucleation and mechanical properties of the fcc-Al/L12-Al3M (M = Sc, Ti, V, Y, Zr, Nb) interface from first-principles calculations

2021 ◽  
Author(s):  
Yu Liu ◽  
Jin-Chuan Wen ◽  
Xie-Yi Zhang ◽  
Yuan-Chun Huang
Keyword(s):  
Mechanical Properties ◽  
Comparative Study ◽  
Heterogeneous Nucleation ◽  
First Principles ◽  
Lattice Misfit ◽  
Electronic Interaction ◽  
First Principles Calculations ◽  
Interfacial Stability

The heterogeneous nucleation and mechanical properties of fcc-Al/L12-Al3M(M = Sc, Ti, V, Y, Zr, Nb) interfaces were compared. The contributions of interfacial lattice misfit and electronic interaction to the interfacial stability are detailed.

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