Influence of Interfacial Structure on Properties of Nickel–Iron Alloys from Red Mud

To understand the effect of the interfacial structure between chromium carbide and the matrix on the properties of nickel–iron alloys from red mud, first-principles density functional theory calculations were conducted. The plane-wave pseudopotential method in the CASTEP software package was used to select the atomic layer numbers and to calculate the surface energies of the FeNi₃ nickel–iron alloy and chromium carbide in the [001] direction, as well as the density of states, differential charge, bonding mode, and tensile properties near the FeNi₃(001)/Cr₃C₂(001) interface. Moreover, the maximum interfacial adhesion energy of the Fe–Ni-terminated interface is 0.478 J/m², the minimum interface spacing is 2.8 Å, and this interface is the most stable. In addition, during a first-principles tensile simulation, the stress reached a maximum value at 12% strain owing to the disruption of the atomic bonds near the interface, and then the stress showed a significant downward trend, indicating that the interface deformation reached the limit and mechanical fracture occurred. This work will aid in the understanding of the strengthening mechanism of nickel–iron alloys from red mud.