Structures, elastic, electronic properties and phase stability of Ni–Sc intermetallic compounds from first-principles investigation

2018 ◽  
Vol 32 (24) ◽  
pp. 1850262 ◽  
Author(s):  
Yali Wu ◽  
Xuefeng Guo
Keyword(s):  
Shear Modulus ◽  
Electronic Properties ◽  
Intermetallic Compounds ◽  
Phase Stability ◽  
First Principles ◽  
Density Functional ◽  
Mechanical Stability ◽  
Ductile Phase ◽  
Covalent Bonds ◽  
Debye Temperatures

First-principles method based on density functional theory has been performed to study the lattice structures, elastic properties, Debye temperatures, electronic properties and phase stability of Ni–Sc intermetallic compounds systematically. The calculated lattice parameters are close to available experimental data. The analysis results of formation enthalpies indicate that the Ni–Sc compounds are all thermodynamically stable and NiSc is the most stable. Besides, these compounds are also mechanically stable according to the mechanical stability criterion. The obtained shear modulus G and Young’s modulus E show that Ni5Sc is the stiffest and the most covalent compound. The discussion about G/B (the ratio of shear modulus to bulk modulous), Poisson’s ratio [Formula: see text] and Cauchy pressure demonstrate that all Ni–Sc compounds are ductile and NiSc2 is the most ductile phase, followed by NiSc. The results of Debye temperatures indicate that Ni5Sc has the stronger covalent bonds than others. Finally, the electronic properties are investigated to reveal the underlying mechanical properties.

scholarly journals ELASTIC PROPERTIES OF TRANSITION METAL DIOXIDES: XO2 (X = Ru, Rh, Os, andIr)

2008 ◽  
Vol 19 (08) ◽  
pp. 1269-1275 ◽  
Author(s):  
YANLING LI ◽  
ZHI ZENG
Keyword(s):  
Density Functional Theory ◽  
Transition Metal ◽  
Shear Modulus ◽  
Elastic Properties ◽  
First Principles ◽  
Density Functional ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Debye Temperatures ◽  
Metal Dioxides

The elastic properties of rutile transition metal dioxides XO2 ( X = Ru , Rh , Os , and Ir ) are investigated using first-principles calculations based on density functional theory. Elastic constants, bulk modulus, shear modulus, and Young's modulus as well as Possion ratio are given. OsO 2 and IrO 2 show strong incompressibility. The hardness estimated for these dioxides shows that they are not superhard solids. The obtained Debye temperatures are comparative to those of transition metal dinitrides or diborides.

scholarly journals Elastic Properties and Electronic Properties of MxNy (M = Ti, Zr) from First Principles Calculations

Materials ◽  
2018 ◽  
Vol 11 (9) ◽  
pp. 1640 ◽  
Author(s):  
Yangqi Ji ◽  
Xiaoli Yuan
Keyword(s):  
Electronic Properties ◽  
Elastic Properties ◽  
First Principles ◽  
Density Functional ◽  
Mechanical Stability ◽  
Central Force ◽  
First Principles Calculations ◽  
Functional Theory ◽  
Space Group ◽  
Group I

The elastic properties and electronic properties of MxNy (M = Ti, Zr) TiN, Ti2N, Zr3N4, ZrN with different structures have been investigated using density functional theory. Through the calculation of the elastic constants, it was found that all of these structures meet the mechanical stability except for ZrN with space group P63mc. Their mechanical properties are studied by a comparison of various parameters. The stiffness of TiN is larger than that of ZrN with space group Fm 3 ¯ m. Ti2N’s stiffness with space group I41/amdz is larger than Ti2N with space group P42/mnm. Zr3N4’s stiffness with space group Pnam is largest in three structures of Zr3N4. TiN, Ti2N and ZrN are non-central force, Zr3N4 is central force. TiN and ZrN with space group Fm 3 ¯ m are brittle, and TiN is brittler than ZrN with space group Fm 3 ¯ m. The two kinds of Ti2N are brittle and Ti2N with space group I41/amdz is larger. Three structures of Zr3N4 are tough and Zr3N4 with space group I 4 ¯ 3d is the toughest. Meanwhile, the electronic properties of TiN, Ti2N, Zr3N4 and ZrN were calculated, possible superconducting properties of the studied materials were predicted.

scholarly journals First-principles investigation of the structural stability and electronic properties of Pd doped monoclinic Cu6Sn5 intermetallic compounds

2014 ◽  
Vol 32 (4) ◽  
pp. 592-596 ◽  
Author(s):  
Wei-Quan Shao ◽  
Wen-Cai Lu ◽  
Sha-Ou Chen
Keyword(s):  
Electronic Properties ◽  
Intermetallic Compounds ◽  
Structural Properties ◽  
Structural Stability ◽  
Surface Finish ◽  
Phase Stability ◽  
First Principles ◽  
Heat Of Formation ◽  
Dominant Factor ◽  
Cu Substrate

AbstractTri-layer Au/Pd/Ni(P) films have been widely used as surface finish over the Cu pads in high-end packaging applications. It was found that a thin (Cu,Pd)6Sn5 IMC layer was beneficial in effective reducing inter-diffusion between a Cu substrate and a solder, and therefore the growth of the IMC layer and the EM (electromigration) processes. In this study, the structural properties and phase stability of monoclinic Cu6Sn5-based structures with Pd substitutions were studied by using the first-principles method. The (Cu,Pd)6Sn5 structure with the 4e site substituted by Pd has the lowest heat of formation and is the most stable among (Cu,Pd)6Sn5 structures. Hybridization of Pd-d and Sn-p states is a dominant factor for stability improvement. Moreover, Pd atoms concentration corresponding to the most stable structure of (Cu,Pd)6Sn5 was found to be 1.69 %, which is consistent with the experimental results.

scholarly journals First-principles insights on mechanical and electronic properties of TiX (X=C,N) in β-Si3N4 based ceramics

2016 ◽  
Vol 10 (3) ◽  
pp. 153-160 ◽  
Author(s):  
Harsha Shanmugakumar ◽  
Nagarajan Veerappan ◽  
Chandiramouli Ramanathan
Keyword(s):  
Density Functional Theory ◽  
Shear Modulus ◽  
Electronic Properties ◽  
Density Of States ◽  
First Principles ◽  
Density Functional ◽  
Si3n4 Ceramic ◽  
Functional Theory ◽  
Clear Insight ◽  
Si3n4 Ceramics

The mechanical and electronic properties of ?-Si3N4, TiC-Si3N4 and TiN-Si3N4 ceramics are investigated using density functional theory implemented with GGA/PBE functional. The pristine ?-Si3N4 exhibits fracture for a strain of 10%. However, TiC-Si3N4 and TiN-Si3N4 ceramics exhibits fracture for a strain of 20%. The Young?s modulus, shear modulus and bulk modulus of the pristine ?-Si3N4, TiC-Si3N4 and TiN-Si3N4 ceramics are reported. TiN-Si3N4 ceramic is found to be the least compressible and hard. The band gap is found to decrease for TiC-Si3N4 and TiN-Si3N4 ceramics comparedwith the pristine ?-Si3N4. The density of states spectrumshows more peak maxima for TiC-Si3N4 and TiN-Si3N4 ceramics rather than ?-Si3N4. The finding of the present work gives a clear insight on the mechanical and electronic properties of ?-Si3N4, TiC-Si3N4 and TiN-Si3N4 ceramics at the atomistic level.

First-Principles Calculations of the Mechanical and Elastic Properties of 2Hc- and 2Ha-WS2/CrS2 Under Pressure

2016 ◽  
Vol 71 (6) ◽  
pp. 517-524 ◽  
Author(s):  
Hua-Long Jiang ◽  
Song-Hao Jia ◽  
Da-Wei Zhou ◽  
Chun-Ying Pu ◽  
Fei-Wu Zhang ◽  
...  
Keyword(s):  
Shear Modulus ◽  
Elastic Properties ◽  
First Principles ◽  
Elastic Moduli ◽  
Mechanical Stability ◽  
First Principles Calculations ◽  
Stability Criteria ◽  
Poisson Coefficient ◽  
Debye Temperatures ◽  
Two Phases

AbstractBy utilizing the first-principles method, the pressure-induced effects on phase transition, mechanical stability, and elastic properties of WS2/CrS2 are investigated in the pressure range from 0 to 80 GPa. Transitions from 2Hc to 2Ha for WS2 and CrS2 are found to occur at 17.5 and 25 GPa, respectively. It is found that both 2Ha and 2Hc phases of WS2 and CrS2 meet the mechanical stability criteria up to 80 GPa, suggesting that those structures are mechanically stable. The bulk and shear modulus anisotropy of the two phases of WS2 and CrS2 decrease rapidly under pressure and, finally, trend to isotropy. With increasing pressure, the elastic moduli (Y, B, and G), sound velocities (vs, vp, vm), and Debye temperatures (Θ) of 2Ha and 2Hc of WS2 and CrS2 increase monotonously. Moreover, the Debye temperature (Θ) of 2Hc phase is higher than that of 2Ha phase for both WS2 and CrS2. The bulk, shear, and Young’s modulus, Poisson coefficient, and brittle/ductile behaviour are estimated. The percentages of anisotropy in compressibility and shear and the ratio of bulk to shear modulus (B/G) are also studied.

Impurity concentration effects on mechanical properties of Al-doped B2-NiSc intermetallics from first-principles investigation

2019 ◽  
Vol 33 (25) ◽  
pp. 1950287
Author(s):  
Yali Wu ◽  
Xuefeng Guo ◽  
Mingke Lei ◽  
Hongbao Cui ◽  
Wenpeng Yang ◽  
...  
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Doping Concentration ◽  
Parent Phase ◽  
Melting Points ◽  
Al Doping ◽  
Concentration Effects ◽  
Site Preferences ◽  
Debye Temperatures

First-principles method based on density functional theory has been performed to study the crystal structures, phase stability, site preferences, elastic properties, hardness, melting points, Debye temperatures and electronic properties of Al-doped B2-NiSc intermetallics with different concentrations systematically. The results show that the Al atom occupies the Sc site preferentially. For the doped systems in which an Sc atom is substituted by one Al atom, the bulk modulus increases as the Al doping concentration increases and is larger than that of pure B2-NiSc. However, the shear modulus and Young’s modulus are smaller than the parent phase. The ductility of B2-NiSc intermetallics can be improved by adding Al element, and it increases with the increase of doping concentration. But, the increase of ductility is accompanied by the decrease of hardness. The melting points of doped alloys are all lower than the parent phase. Besides, on the basis of the calculated electronic properties, Al doping weakens covalent bonding and enhances the metal bonding of Al-doped NiSc.

scholarly journals Phase stability, elastic and electronic properties of Hf–Rh intermetallic compounds from first-principles calculations

RSC Advances ◽  
2017 ◽  
Vol 7 (33) ◽  
pp. 20241-20251 ◽  
Author(s):  
Mingliang Wang ◽  
Cunjuan Xia ◽  
Yi Wu ◽  
Dong Chen ◽  
Zhe Chen ◽  
...  
Keyword(s):  
Bulk Modulus ◽  
Linear Relationship ◽  
Electronic Properties ◽  
Intermetallic Compounds ◽  
Phase Stability ◽  
First Principles ◽  
First Principles Calculations ◽  
Atomic Concentration

The calculated bulk modulus has a linear relationship with the atomic concentration of Rh in the binary Hf–Rh compounds.

Mechanical and electronic properties of Ti2AlN and Ti4AlN3: a first-principles study

2014 ◽  
Vol 92 (12) ◽  
pp. 1652-1657 ◽  
Author(s):  
Wenxia Feng ◽  
Shouxin Cui
Keyword(s):  
Electronic Properties ◽  
First Principles ◽  
Density Functional ◽  
Mechanical Stability ◽  
Tensile Deformation ◽  
Structural Failure ◽  
Modulus Ratio ◽  
Electronic Band ◽  
Cauchy Pressure ◽  
Electronic Band Structures

Investigations into the electronic properties, elastic properties, and ideal tensile strengths for Ti2AlN and Ti4AlN3 were conducted using first-principles density functional calculations. The electronic band structures and density of states show metallic conductivity in which Ti 3d states dominate for Ti2AlN and Ti4AlN3. Moreover, the hybridization peak of Ti 3d and N 2p lies at a lower energy than that of Ti 3d and Al 3p, which suggests that the Ti 3d – N 2p bond is stronger than the Ti 3d – Al 3p bond. The variations of elastic constants with pressure indicate that Ti2AlN and Ti4AlN3 possess higher mechanical stability in the pressure range 0–100 GPa. By calculating the bulk-modulus-to-shear-modulus ratio and Cauchy pressure, we predict that Ti2AlN and Ti4AlN3 are brittle. We show that the structural failure of these ternary compounds can be ascribed to the breakage of weak Ti–Al bonds under uniaxial tension and that layered structural stability is determined by the strength of the Ti–Al bond under tensile deformation.

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