First-Principles Study on Al/Al3Hf Heterogeneous Nucleation Interface

Abstract

Using first-principles method, the work of adhesion (Wad) and electronic structure of Al3Hf (001)/Al (001) interface are studied and the mechanism of Al3Hf as enhanced heterogeneous nucleus of α-Al are discussed. The results indicate that Al + Hf-termination interfaces with same stacking sequence and the HCP (Al atom locating on top of the Al3Hf slab) interface with the same termination have maximum Wad and minimum interface energy (yint), and therefore they are more stable ones. It is noteworthy that Al + Hf-terminated interface with HCP is most steady one. The stacking of Al atoms on Al3Hf substrates tend to occur in this way. Besides, electronic structures indicate that Al + Hf-terminated interfaces have stronger electronic interaction than that of Al-terminated ones and the Al-Hf bonds of Al + Hf-terminated interface with HCP stacking tend to covalent bonds, while Al–Al bonds of Al-terminated one are metal bonds. Al3Hf as enhanced heterogeneous nucleation of α-Al are effective from crystallography and thermodynamics.