A first-principles study of the diffusion coefficients of alloying elements in dilute α-Ti alloys

2016 ◽  
Vol 18 (25) ◽  
pp. 16870-16881 ◽  
Author(s):  
W. W. Xu ◽  
S. L. Shang ◽  
B. C. Zhou ◽  
Y. Wang ◽  
L. J. Chen ◽  
...  
Keyword(s):  
Chemical Bonding ◽  
First Principles ◽  
Diffusion Coefficients ◽  
Alloying Elements ◽  
Solute Diffusion ◽  
Key Factors ◽  
Comprehensive Investigation ◽  
Ti Alloys ◽  
Vibrational Features ◽  
Bonding Characteristics

We present a comprehensive investigation of the diffusion of alloying elements X in dilute α-Ti alloys. Besides the effect of solute size, two other key factors governing solute diffusion in dilute α-Ti are clarified: the chemical bonding characteristics and vibrational features of X–Ti pairs.

First-Principles Study on Chemical Bonding Characteristics between Cr and Single-Walled Silicon Nanotubes

2013 ◽  
Vol 798-799 ◽  
pp. 30-34
Author(s):  
Ai Qing Wu ◽  
Li Yang
Keyword(s):  
Carbon Nanotubes ◽  
Structural Properties ◽  
Adsorption Energy ◽  
Chemical Bonding ◽  
First Principles ◽  
Subsequent Formation ◽  
Silicon Nanotubes ◽  
Hole Position ◽  
Hybrid Orbital ◽  
Bonding Characteristics

The adsorption energy and structural properties of Cr doped armchair (5, 5) single-walled silicon or Carbon nanotubes are investigated in detail by the first-principles theory. It is found that Cr atom above on hole position is most energetically favorable for SWSiNTs, which means that Cr atom is prone to absorb on Silicon nanotubes than Carbon nanotubes. Structural analyses suggest that Cr adsorption in silicon nanotubes induces the dehybridization of mixed sp2-sp3hybrid orbital and the subsequent formation of sp3-like orbital. That enhances the adsorption energy of silicon nanotubes.

scholarly journals Data set for diffusion coefficients of alloying elements in dilute Mg alloys from first-principles

Data in Brief ◽  
2015 ◽  
Vol 5 ◽  
pp. 900-912 ◽  
Author(s):  
Bi-Cheng Zhou ◽  
Shun-Li Shang ◽  
Yi Wang ◽  
Zi-Kui Liu
Keyword(s):  
First Principles ◽  
Diffusion Coefficients ◽  
Mg Alloys ◽  
Alloying Elements ◽  
Data Set

Site preference and atomic ordering in the ternary Rh5Ga2As: first-principles calculations

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Nilanjan Roy ◽  
Sucharita Giri ◽  
Harshit ◽  
Partha P. Jana
Keyword(s):  
Total Energy ◽  
First Principles ◽  
Density Functional ◽  
Structure Type ◽  
Site Preference ◽  
X Ray Diffraction ◽  
Atomic Ordering ◽  
Functional Theory ◽  
The Stability ◽  
Bonding Characteristics

Abstract The site preference and atomic ordering of the ternary Rh5Ga2As have been investigated using first-principles density functional theory (DFT). An interesting atomic ordering of two neighboring elements Ga and As reported in the structure of Rh5Ga2As by X-ray diffraction data only is confirmed by first-principles total-energy calculations. The previously reported experimental model with Ga/As ordering is indeed the most stable in the structure of Rh5Ga2As. The calculation detected that there is an obvious trend concerning the influence of the heteroatomic Rh–Ga/As contacts on the calculated total energy. Interestingly, the orderly distribution of As and Ga that is found in the binary GaAs (Zinc-blende structure type), retained to ternary Rh5Ga2As. The density of states (DOS) and Crystal Orbital Hamiltonian Population (COHP) are calculated to enlighten the stability and bonding characteristics in the structure of Rh5Ga2As. The bonding analysis also confirms that Rh–Ga/As short contacts are the major driving force towards the overall stability of the compound.

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.

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