High-throughput first-principles investigation on grain boundary segregation of alloying elements in ferritic steel

By employing high-throughput first-principles calculations, the segregation capacity of fifteen widely used metallic alloying elements (viz., Be, Mn, Co, Cr, Ni, Al, Mo, W, Mg, Ta, Nb, Sb, Sn, Zr, and Bi) at ∑3 grain boundary in low alloy ferritic steel, as well as their impact on grain boundary stability, interfacial separation work, and other properties, were systematically investigated. The findings reveal that, for alloying atoms Sb, Sn, Bi, Nb, and Zr, whose size is notably larger than that of the matrix Fe atoms, the effect of strain energy minimization in segregation is comparable to that of chemical energy minimization. Furthermore, the impact of strain energy minimization is closely related to the volume of the alloying atoms both at the solid solution sites in the crystal and at the segregation sites at the grain boundary. Thus, the segregation of large alloy atoms on the grain boundaries can be predicted by atomic volume of each segregation site, which can provide valuable insights for the development of new alloys and for grain boundary engineering.