A universal descriptor to determine the effect of solutes in segregation at grain boundaries

The control of solute segregation at grain boundaries is of significance in engineering alloy properties. However, there is currently a lack of a physics-informed predictive model for estimating solute segregation energies. Here we propose novel electronic descriptors for grain-boundary segregation based on the valence, electronegativity and size of solutes. By integrating the non-local coordination number of surfaces, we build a predictive analytic framework for evaluating the segregation energies across various solutes, grain-boundary structures, and segregation sites. This framework uncovers not only the coupling rule of solutes and matrices, but also the origin of solute-segregation determinants, which stems from the d- and sp-states hybridization in alloying. Our scheme establishes a novel picture for grain-boundary segregation and provides a useful tool for the design of advanced alloys.