scholarly journals Lattice Stability and Elastic Properties of Zr-Ti-X Alloys (X = Al, V) by the First Principles Study

Metals ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1317
Author(s):  
Wenxiong Duan ◽  
Xiaoping Liang ◽  
Xiangguan Yang ◽  
Yu Wang ◽  
Baifeng Luan
Keyword(s):  
Mechanical Properties ◽  
Elastic Properties ◽  
First Principles ◽  
Mass Fraction ◽  
Point Of View ◽  
Lattice Stability ◽  
Lattice Constants ◽  
Al Content ◽  
Hexagonal Close Packed ◽  
Β Phase

Based on a certain ratio of Zr and Ti atomic fractions according to Zr47Ti45Al5V3 (wt.%), the lattice constants, lattice stability, and elastic properties of Zr-Ti-X alloys (X = Al, V) in body-centered cubic (BCC) (β phase) and hexagonal close-packed (HCP) (α phase) crystal structures were studied using first-principles calculations. It is shown that Al acts as an α stabilizer for Zr-Ti-Al alloys and V can stabilize the β phase for Zr-Ti-V alloys. As the mass fraction of Al increases from 4 wt.% (Zr55Ti41Al4) to 6.8 wt.% (Zr53.2Ti40Al6.8), these alloys all have relatively good strength, hardness, and rigidity, however, their ductility deteriorated with the increasing of Al mass fraction. When the mass fraction of V in Zr-Ti-V alloys is 2.4 wt.%, Zr55.6Ti42V2.4 (wt.%) achieved the best strength, hardness, and rigidity, when the mass fraction of V increases from 0 (Zr57Ti43) to 12 wt.% (Zr50.2Ti37.8V12), their ductility improved. The changes of phase compositions and structure with Al content or V content distinctly affect mechanical properties of ternary Zr-Ti-X alloys (X = Al, V), the amount of Zr and Ti could be factors that impact the mechanical properties of the multiphase Zr47Ti45Al5V3 from the point of view of ternary Zr-Ti-Al and Zr-Ti-V compositions.

scholarly journals First principles computation of composition dependent elastic constants of omega in titanium alloys: implications on mechanical behavior

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
R. Salloom ◽  
S. A. Mantri ◽  
R. Banerjee ◽  
S. G. Srinivasan
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
First Principles ◽  
Young's Modulus ◽  
Group Vi ◽  
Group V ◽  
Β Phase ◽  
Ti Alloys ◽  
Ω Phase ◽  
Stabilizer Concentration

AbstractFor decades the poor mechanical properties of Ti alloys were attributed to the intrinsic brittleness of the hexagonal ω-phase that has fewer than 5-independent slip systems. We contradict this conventional wisdom by coupling first-principles and cluster expansion calculations with experiments. We show that the elastic properties of the ω-phase can be systematically varied as a function of its composition to enhance both the ductility and strength of the Ti-alloy. Studies with five prototypical β-stabilizer solutes (Nb, Ta, V, Mo, and W) show that increasing β-stabilizer concentration destabilizes the ω-phase, in agreement with experiments. The Young’s modulus of ω-phase also decreased at larger concentration of β-stabilizers. Within the region of ω-phase stability, addition of Nb, Ta, and V (Group-V elements) decreased Young’s modulus more steeply compared to Mo and W (Group-VI elements) additions. The higher values of Young’s modulus of Ti–W and Ti–Mo binaries is related to the stronger stabilization of ω-phase due to the higher number of valence electrons. Density of states (DOS) calculations also revealed a stronger covalent bonding in the ω-phase compared to a metallic bonding in β-phase, and indicate that alloying is a promising route to enhance the ω-phase’s ductility. Overall, the mechanical properties of ω-phase predicted by our calculations agree well with the available experiments. Importantly, our study reveals that ω precipitates are not intrinsically embrittling and detrimental, and that we can create Ti-alloys with both good ductility and strength by tailoring ω precipitates' composition instead of completely eliminating them.

First Principles Study of Elastic Properties, Mechanical Properties and Electronic Band Structures of LiGaO2 Phases

2021 ◽  
Vol 223 (1) ◽  
pp. 68-80
Author(s):  
Thanit Saisopa ◽  
Chakrit Nualchimplee ◽  
Yuttakarn Rattanachai ◽  
Kompichit Seehamart ◽  
Isara Kotutha ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Elastic Properties ◽  
First Principles ◽  
Band Structures ◽  
Electronic Band ◽  
First Principles Study ◽  
Electronic Band Structures

Design of High Elastic Modulus Alloy Using First Principles Electronic Theory

1990 ◽  
Vol 186 ◽  
Author(s):  
K. Masuda-Jindo ◽  
K. Terakura
Keyword(s):  
Elastic Modulus ◽  
Elastic Properties ◽  
First Principles ◽  
Theoretical Calculations ◽  
Spherical Wave ◽  
Wave Method ◽  
Lattice Constants ◽  
Simple Curves ◽  
Solute Atoms ◽  
Fcc Alloys

AbstractThe first principles ASW (augmented spherical wave) method is used to predict the elastic properties of Al-base and Ni-base fcc alloys. It is shown that the elastic modulus increase or decrease of the fcc alloys is closely correlated with the change in the lattice constants and that the results for various solute atoms can be summarized in the simple curves, depending on the species of the solute atoms. We demonstrate that the theoretical calculations for the binary alloys can be used for the design of the (multi-component) fcc alloys with desired elastic properties and lattice constants.

The tunable electronic structure and mechanical properties of halogenated silicene: a first-principles study

2015 ◽  
Vol 3 (13) ◽  
pp. 3087-3094 ◽  
Author(s):  
Wei-Bing Zhang ◽  
Zhi-Bo Song ◽  
Liu-Ming Dou
Keyword(s):  
Mechanical Properties ◽  
Electronic Structure ◽  
Effective Mass ◽  
Elastic Properties ◽  
First Principles ◽  
First Principles Study ◽  
Carrier Effective Mass ◽  
Enhanced Stability

Halogenated silicene, with enhanced stability compared with silicene, presents a moderate and tunable direct gap with small carrier effective mass and improved elastic properties.

scholarly journals The layered uranyl silicate mineral uranophane-β: crystal structure, mechanical properties, Raman spectrum and comparison with the α-polymorph

2019 ◽  
Vol 48 (44) ◽  
pp. 16722-16736 ◽  
Author(s):  
Francisco Colmenero ◽  
Jakub Plášil ◽  
Jiří Sejkora
Keyword(s):  
Crystal Structure ◽  
Mechanical Properties ◽  
Raman Spectrum ◽  
Solid State ◽  
Elastic Properties ◽  
First Principles ◽  
Silicate Mineral

The crystal structure, elastic properties and Raman spectrum of the calcium uranyl silicate pentahydrate mineral uranophane-β, are studied using first-principles solid-state methods and compared with the corresponding information for the α polymorph.

scholarly journals Mechanical and Electronic Properties of DNTF Crystals under Different Pressure

Crystals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1180
Author(s):  
Hai Nan ◽  
Xianzhen Jia ◽  
Xuanjun Wang ◽  
Heping Liu ◽  
Fan Jiang ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Charge Density ◽  
Electronic Properties ◽  
Elastic Properties ◽  
First Principles ◽  
Great Influence ◽  
Shear Resistance ◽  
Variation Trend ◽  
Lattice Constants ◽  
First Principles Method

In the present study, the effects of pressure on the structure, elastic properties and electronic structure of DNTF compounds are studied using the first principles method. It is found that pressure has a great influence on lattice constants. When the pressure reaches 80 GPa, the structure of DNTF changes suddenly. The variation trend of C11, C22 and C33 values is consistent with that of pressure. In addition, pressure can improve the compressibility and shear resistance of the DNTF compound. The pressure can reduce the bandgap and further increases the charge density, causing DNTF to decompose and explode.

The Lattice Stability of Ti, Zr and Hf in an Ultra-Soft Pseudopotential Method of the First-Principles

2011 ◽  
Vol 399-401 ◽  
pp. 2203-2209
Author(s):  
Hui Jin Tao ◽  
Jian Yin
Keyword(s):  
Heavy Metals ◽  
First Principles ◽  
Electronic Structures ◽  
Lattice Stability ◽  
Lattice Constants ◽  
Densities Of States ◽  
Total Energies ◽  
Projector Augmented Wave ◽  
Atomic Populations ◽  
State Increase

The lattice constants, total energies and densities of states of Ti, Zr and Hf in ⅣB group with different crystalline structures have been calculated, and the results have been compared with the results of the projector augmented wave (PAW) method in first-principles, CALPHAD and experiments. It is found that the results of lattice stability in this paper agree completely with those of the PAW method in first-principles and agree well with those of CALPHAD. Further analyses of lattice stability from electronic structures show that the crystalline Ti,Zr and Hf with hcp structures have the obvious character of stable phases, but fcc and bcc structures have the character of metastable and unstable phases, agreeing with the results of total energy calculations. It is found from the analyses of atomic populations that the transiton numbers of electrons from the s state to the p and d states for the hcp, fcc and bcc crystals decrease with the increase in elemental period, and the transiton number of electrons from the s state to the p state decrease dramatically, but the transiton from the s state to the d state increase dramatically, leading to much more number of electrons in the d state than that in the s or p state, stronger cohesion or higher cohesive energy between atoms in heavy metals and accordingly the stabler lattice in these heavier metals.

Effects of Strain on the Half-Metallic and Elastic Properties of FeCrTe and CoCrSi with Clb Structure

SPIN ◽  
2019 ◽  
Vol 09 (03) ◽  
pp. 1950018 ◽  
Author(s):  
Moaid K. Hussain
Keyword(s):  
Elastic Properties ◽  
Spin Polarization ◽  
First Principles ◽  
Mechanical Stability ◽  
First Principles Calculation ◽  
Half Metallic ◽  
Lattice Constants ◽  
Elastic Characteristics

The effects of strain on the half-metallic (HM) and elastic properties of FeCrTe and CoCrSi alloys with Clb structure were calculated using a first-principles calculation. Both compounds showed (HM) property with full spin polarization, and this property can be present when their lattice constants are in the range from 5.18 Å to 5.71 Å for CoCrSi, and 5.25 Å to 6.05 Å for FeCrTe. The calculations of elastic properties show that both compounds are mechanically stable, ductile and hard with varied properties. In addition, calculations of the elastic characteristics for the above ranges for both FeCrTe and CoCrSi alloys showed mechanical stability, therefore, the FeCrTe and CoCrSi alloys are likely to be composed in experimental applications.

Ternary Diagrams of Ni-Mn-Ga from First Principles

2016 ◽  
Vol 845 ◽  
pp. 130-133 ◽  
Author(s):  
Vladimir V. Sokolovskiy ◽  
Yuliya A. Sokolovskaya ◽  
Mikhail A. Zagrebin ◽  
Vasiliy D. Buchelnikov ◽  
Alexey T. Zayak
Keyword(s):  
Ab Initio Calculations ◽  
Bulk Modulus ◽  
Ab Initio ◽  
Elastic Properties ◽  
First Principles ◽  
Coherent Potential Approximation ◽  
Potential Approximation ◽  
Lattice Constants ◽  
Ternary Diagrams ◽  
Formation Energies

The composition dependences of the magnetic and elastic properties of Ni-Mn-Ga Heusleralloys are investigated by using ab initio calculations. The off-stoichiometric compositions are real-ized by the coherent-potential approximation. Two types of off-stoichiometric approaches are pro-posed. Through a series of researches, the equilibrium lattice constants, bulk modulus, magnetic mo-ments, formation energies of Ni-Mn-Ga alloys are obtained and mapped onto ternary diagrams.

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