The Al(x)MoNbTiV (x = 0-1.5) high-entropy alloys (HEAs) adopt a single solid-solution phase, having the body centered cubic (bcc) crystal structure. Here we employ the ab initio exact muffin-tin orbitals method in combination with the coherent potential approximation to investigate the equilibrium volume, elastic constants, and polycrystalline elastic moduli of Al(x)MoNbTiV HEAs. A comparison between the ab initio and experimental equilibrium volumes demonstrates the validity and accuracy of the present approach. Our results indicate that Al addition decreases the thermodynamic stability of the bcc structure with respect to face-centered cubic and hexagonal close packed lattices. For the elastically isotropic Al(0.4)MoNbTiV HEAs, the valence electron concentration (VEC) is about 4.82, which is slightly different from VEC ∼ 4.72 obtained for the isotropic Gum metals and refractory--HEAs.

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The combined effects of nonadiabatic dust charge fluctuation, ultraviolet irradiation, and transverse perturbation on the modulational instability of nonlinear dust acoustic (DA) waves in dusty plasma consisting of Boltzmann-distributed electrons, ions, as well as positively charged dust grain were presented here. By using the reductive perturbation technique, a three-dimensional modified Davey–Stewartson equation governing the nonlinear waves is derived. It is shown that the modulation properties of the DA waves were strongly affected by the nonadiabatic dust charge variation and photoelectrons and there was a maximum time for the modulational instability.

On the basis of the first principle interatomic potentials, the site preference of various alloying elements in Fe 3 Al were evaluated for Ti, Si, Ni, Mn, Mo, and Cr, respectively. The calculated results of the substitutional distribution were in good agreement with the experimental results. Moreover, the calculated results showed that H atoms in Fe 3 Al prefer to occupy the Fe-type octahedral interstice on the surface, which resulted in concentration of H atoms on the surface. Cr addition decreased the absorbability of Fe 3 Al-based alloys for H atoms and the force to drive H atoms segregating to surface. The concentration of H atoms on the surface can be decreased by Cr addition.

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