Effects of Zr-Re/W co-segregation behavior on the thermodynamic stability and fracture strength of γ-Ni/γ'-Ni3Al interface

Abstract

First-principles calculations based on density functional theory were employed to investigate the Zr-Re/W co-segregations at the γ-Ni/γ'-Ni3Al interface and their effects on the stability and binding strength. It is found W/Re can segregate at the γ-L1-3.52-cp site of the γ-Ni (001) layer in the Zr-segregated interface which is the most stable. The stability of Zr-W/Re co-segregated interface is improved and becomes more stable than clean and Zr-segregated interfaces, due to the existence of pseudogaps at the Fermi level. The co-segregations of Zr-W/Re atoms do not change the final fracture place of γ-Ni/γ'-Ni3Al interface as compared with the Zr-segregated and clean interfaces. The co-segregations slightly enhance the fracture strength of Zr-segregated interface when interfacial fracture occurs in region-1, while is improved and even stronger than the clean interface as the fracture in region-2. Also, the binding energies of Zr-W/Re were calculated to elucidate the interatomic interactions, which contribute to interfacial strength.