Revealing the Epitaxial Interface between Al13Fe4 and Al5Fe2 Enabling Atomic Al Interdiffusion

Steel is the most commonly manufactured material in the world. Its performances can be improved by hot-dip coating with the low weight aluminum metal. The structure of the Al parallel to Fe interface, which is known to contain a buffer layer made of complex intermetallic compounds such as Al5Fe2 and Al13Fe4, is crucial for the properties. On the basis of surface X-ray diffraction, combined with theoretical calculations, we derive in this work a consistent model at the atomic scale for the complex Al13Fe4(010) parallel to Al5Fe2(001) interface. The epitaxial relationships are found to be [130]Al5Fe2 parallel to[010]Al13Fe4 and [1 1 constrained energies, as well as works of adhesion, calculated for several structural models based on density functional theory, identify the lattice mismatch and the interfacial chemical composition as main factors for the stability of the interface. Molecular dynamics simulations suggest a mechanism of Al diffusion to explain the formation of the complex Al13Fe4 and Al5Fe2 phases at the Al parallel to Fe interface. KEYWORDS: surface X-ray diffraction, density functional theory, Al-Fe interface, adhesion, Al13Fe4, Al5Fe2 0]Al5Fe2 parallel to[100]Al13Fe4. Interfacial and