Understanding the coupling mechanism of solutes and vacancies in Al and Mg

The solute–vacancy interactions play a crucial role in determining the strength of alloys, yet their underlying mechanisms remain elusive. Here, we introduce a novel descriptor-based framework to understand the mechanisms from an electronic structure perspective. By utilizing intrinsic solute properties, namely, cohesive energy and electronegativity, we uncover the electronic orbital coupling mechanism that dictates solute and vacancy binding. This approach predicts the trends of solute and vacancy interactions and the strengthening effects in microalloyed systems. Our framework not only advances the mechanistic understanding of microalloying but also offers a practical pathway for the design of high-performance alloys.