Solute clustering governed elastic properties in aluminum

Here, we report an extensive screening of homoatomic solute-solute binding energies and calculate the resulting elastic moduli in aluminum using density functional theory. Following a full-configuration strategy, a robust solute clustering map made up of 65 elements is established. Deriving from elemental and DFT-calculated properties, a total of 20 atomistic descriptors are used to evaluate the contributions of cluster bindings. A volume-effect dominated solute atomic binding mechanism is proposed. It suggests that not only the central zone but also the outer Al shell responds to solute bindings. The impact of stable solute clusters on the elastic properties of Al alloys is calculated. An unconventional enhancement mechanism of Young's modulus in these Al-based alloys is proposed. Based on the interatomic interaction forces derived elastic response theory, modified ‘atomic distance-electron density-Young's modulus' models applying to different element groups are proposed. Our work is expected to provide insight into the design of high strength, and high stiffness Al alloys.