First-principle study of interfacial properties of Ni-Ni3Si composite

In order to explore the interfacial structure of Ni/Ni3Si (0 0 1) interfaces and clarify the heterogeneous nucleation potential of α-Ni grains on Ni3Si particles in Ni-Ni3Si eutectic alloys, the work of adhesion, electronic structure, and interface energy have been studied by first-principle method based on density functional theory (DFT). Surface convergence tests show that Ni3Si (0 0 1) slabs with more than eight layers exhibit bulk-like interior feature. The values of adhesion work and interfacial distance suggest the Ni + Si-terminated interface with hollow site stacking is the most thermodynamic stable and has the largest critical stress for crack propagation among the four models, indicating the precipitates of Ni3Si can improve stability and tensile strength of alloys. This interface has covalent feature, which is mainly contributed by the hybridization of Ni-3d and Si-3p orbital electron. The calculated interface energy of Ni/Ni3Si (0 0 1) interface is smaller than that between the α-Ni and nickel melts, elucidating the excellent nucleation potency of Ni3Si particles for α-Ni grains from thermodynamic considerations.