First-principles studies on lattice constants and local lattice distortions in solid solution aluminum alloys

Changes in the lattice constants of 55 Al-based solid solutions, as well as local lattice distortions induced by solute atoms, were studied on the basis of first-principles calculations using 3.70, 3.13, 1.56, and 0.93 at.% alloys. The first nearest-neighbor interatomic distances between the solute and the solvent Al atoms were relatively constant for all calculated Al–X systems. The calculated volume size factor and the misfit strain were in good agreement with the experimental data available in the literature. The linear relationship observed between the misfit strain and the volume size factor was explained by using the Eshelby approach. A discussion of the application of the misfit strains to the estimation of increasing yield stress due to the solid solution strengthening was also presented. The calculated extent of solid solution strengthening was in good agreement with the available experimental values.

► In 55 Al–X systems, the volume size factors and the misfit strains were obtained. ► The misfit strains at the first nearest-neighbor sites are interaction free. ► The misfit strain increases linearly as the volume size factor increases. ► The effective atomic radius is generally different from the Goldschmidt radius. ► The extent of solid solution strengthening was calculated using the misfit strains.