First-principles study of Al/Al3Ni interfaces

Abstract

Al-Ni alloys have shown promise for high-temperature applications due to the strengthening of Al3Ni fibers resistant to coarsening and spheroidization up to 400°C. While the interface between Al and Al3Ni phases affects the coarsening rate of Al3Ni at elevated temperatures, its characteristics are largely unknown to date. We have constructed various supercells to model this interface and performed a first-principles study based on density functional theory (DFT). We have considered three groups of Al/Al3Ni interfaces: experimentally reported orientation relationships from the solidification studies, crystallographically similar Fe-Fe3C pearlite interfaces, and the family of low-index (100) termination planes. We have analyzed the correlation between the DFT Al/Al3Ni interfacial energies and characteristic features, e.g., excess free volume and the number of broken bonds. We outline the further experimental and computational analysis required to improve the interface modeling of Al/Al3Ni.