Electronic origin of Suzuki segregation of transition metal elements in face-centered cubic Co and Ni alloys

Abstract

Solute segregation to stacking faults (also known as Suzuki segregation) has been employed to stabilize the planar defects to design desired plastic deformation mechanisms in Co- and Ni-based alloys. However, the solute segregation behaviors in intrinsic stacking faults (ISF) and the electronic origin of the segregation remain unclear in face-centered cubic Co- and Ni-alloys. In this study, we predicted the solute-ISF interaction energy for 3d, 4d, and 5d transition metal elements in FCC Co and Ni, using first-principles density functional theory calculations. The driving force of segregation can be attributed to the confluence of the local atomic distortions, charge density redistribution, electron orbital interactions, and local magnetic interactions between the solute and the solvent atoms. These driving forces and the relationships can be utilized in future alloy design efforts to improve mechanical properties via Suzuki segregation to planar defects.