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- Fu, Jie, et al.
(författare)
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Improved Finnis-Sinclair potential for vanadium-rich V-Ti-Cr ternary alloys
- 2017
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Ingår i: Journal of Alloys and Compounds. - : Elsevier BV. - 0925-8388 .- 1873-4669. ; 705, s. 369-375
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Tidskriftsartikel (refereegranskat)abstract
- We have developed an improved Finnis-Sinclair (IFS) potential for vanadium-rich V-Ti-Cr random alloys with body-centred cubic structure. An extra exponential term is added to the original FS potential to enhance the repulsive interaction. The IFS potential is fitted to experimental crystal structure, cohesive energy and elastic constants of pure metals (V, Ti and Cr) and theoretical data of binary alloys (V15Ti, V15Cr and Ti8Cr8). The good agreement of the predicted formation energies of mono-vacancy and selfinterstitial of octahedral interstitial site, tetrahedral interstitial site, < 111>-dumbbell, < 110>-dumbbell, and < 100>-dumbbell with available experimental and theoretical data confirms the validity of our IFS potential in pure V. Furthermore, the agreement of elastic properties and defect properties of typical alloy (V-4-Ti-4-Cr) with experimental or DFT data also support the applicability of the IFS potential in Vrich ternary V-Ti-Cr alloys. Finally, this work also provides a reference to develop empirical potentials for other ternary alloys.
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| 3. |
- Li, Xiaoqing, et al.
(författare)
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Elastic anharmonicity of bcc Fe and Fe-based random alloys from first-principles calculations
- 2017
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Ingår i: Physical Review B. - : American Physical Society. - 2469-9950 .- 2469-9969. ; 95:2
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Tidskriftsartikel (refereegranskat)abstract
- We systematically investigate elastic anharmonic behavior in ferromagnetic body-centered cubic (bcc) Fe and Fe1-xMx (M = Al, V, Cr, Co, or Ni) random alloys by means of density-functional simulations. To benchmark computational accuracy, three ab initio codes are used to obtain the complete set of second-and third-order elastic constants (TOECs) for bcc Fe. The TOECs of Fe1-xMx alloys are studied employing the first-principles alloy theory formulated within the exact muffin-tin orbital method in combination with the coherent-potential approximation. It is found that the alloying effects on C-111, C-112, and C-123, which are governed by normal strains only, are more pronounced than those on C-144, C-166, and C-456, which involve shear strains. Remarkably, the magnitudes of all TOECs but C-123 decrease upon alloying with Al, V, Cr, Co, or Ni. Using the computed TOECs, we study compositional effects on the pressure derivatives of the effective elastic constants (dB(ij)/dP), bulk (dK/dP), and shear moduli (dG/dP) and derive longitudinal acoustic nonlinearity parameters (beta). Our predictions show that the pressure derivatives of K and G decrease with x for all solute elements and reveal a strong correlation between the compositional trends on dK/dP and dG/dP arising from the fact that alloying predominantly altersdB(11)/dP. The sensitivity of dB(11)/dP to composition is attributed to intrinsic alloying effects as opposed to lattice parameter changes accompanying solute addition. For Fe and the considered Fe-based alloys, beta along high-symmetry directions orders as beta[111] > beta[100] > beta[110], and alloying increases the directional anisotropy of beta but reduces its magnitude.
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