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The effects of pressure on the structural, electronic and mechanical properties of tetragonal NbAl 3 and cubic Nb 3 Al have been investigated using first-principles density functional theory approach within the generalized gradient approximation. The calculated structural parameters of two compounds were in good agreement with previous theoretical and experimental data, which linearly decreased with the increasing pressure. The electronic properties of two compounds under pressure have been analyzed. The enhanced covalence under pressure was found due to the increased hybridization between Nb-4d and Al-3p states. The independent elastic constants and mechanical properties have been calculated under pressure. We found that the pressure had a very important influence on mechanical properties. Finally, the ductile/brittle character and mechanical stability of two compounds have been discussed. [ABSTRACT FROM AUTHOR]

Density functional theory (DFT) based first-principles investigation has been performed to study the cohesive, elastic and electronic properties of Fe–Zr binary intermetallics across the composition range. Our initial calibration of underlying DFT approximations provides good agreement of lattice parameters and bulk moduli with experimental results. Ground state stability analysis indicates C15-Fe 2 Zr Laves phase to be the most stable and t-FeZr 2 to be more stable than c-FeZr 2 . All Fe–Zr intermetallics are mechanically stable as estimated from their calculated elastic constants. The calculated elastic moduli, in general, decrease with increasing Zr concentration. Anisotropies in bulk, shear and Young moduli are also presented. All the binary intermetallic phases exhibit G/B value of less than 0.57 and hence are ductile due to the presence of dominant metallic bonding arising from Fe d –Zr d interactions with a small component of covalent character. [ABSTRACT FROM AUTHOR]